Backporting the 32-bit installer requires an additional .wse script,

copied here verbatim from the trunk (it should be release-independent).

PCbuild/uninstal.wse

+Document Type: WSE
+item: Global
+  Version=8.14
+  Flags=00000100
+  Split=1420
+  Languages=65 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+  Copy Default=1
+  Japanese Font Name=MS Gothic
+  Japanese Font Size=10
+  Start Gradient=0 0 255
+  End Gradient=0 0 0
+  Windows Flags=00000000000000000000101000001000
+  Message Font=MS Sans Serif
+  Font Size=8
+  Disk Label=GLBS
+  Disk Filename=INSTALL
+  Patch Flags=0000000000000001
+  Patch Threshold=200
+  Patch Memory=4096
+  Per-User Version ID=1
+  Crystal Format=10111100101100000010001001001001
+  Step View=&Properties
+end
+item: Remark
+  Text=Note from Tim:  This is a verbatim copy of Wise's Uninstal.wse, altered at the end to write
+end
+item: Remark
+  Text=uninstall info under HKCU instead of HKLM if our DOADMIN var is false.
+end
+item: Remark
+end
+item: Remark
+  Text=     Install Support for uninstalling the application.
+end
+item: Remark
+end
+item: Set Variable
+  Variable=UNINSTALL_PATH
+  Value=%_LOGFILE_PATH_%
+  Flags=00000010
+end
+item: Set Variable
+  Variable=UNINSTALL_PATH
+  Value=%UNINSTALL_PATH%\UNWISE.EXE
+end
+item: Compiler Variable If
+  Variable=_EXE_OS_TYPE_
+  Value=WIN32
+end
+item: Install File
+  Source=%_WISE_%\UNWISE32.EXE
+  Destination=%UNINSTALL_PATH%
+  Flags=0000000000000010
+end
+item: Compiler Variable Else
+end
+item: Install File
+  Source=%_WISE_%\UNWISE.EXE
+  Destination=%UNINSTALL_PATH%
+  Flags=0000000000000010
+end
+item: Compiler Variable End
+end
+item: Remark
+end
+item: Remark
+  Text=     Install Support for multiple languages
+end
+item: Remark
+end
+item: Set Variable
+  Variable=UNINSTALL_LANG
+  Value=%UNINSTALL_PATH%
+  Flags=00000010
+end
+item: Set Variable
+  Variable=UNINSTALL_LANG
+  Value=%UNINSTALL_LANG%\UNWISE.INI
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=C
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.FRA
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_C_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.FRA
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=D
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.FRA
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_D_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.FRA
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=E
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.DEU
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_E_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.DEU
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=F
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.PTG
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_F_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.PTG
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=G
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.ESP
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_G_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.ESP
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=H
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.ESP
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_H_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.ESP
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=I
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.ITA
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_I_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.ITA
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=J
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.DAN
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_J_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.DAN
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=K
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.FIN
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_K_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.FIN
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=L
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.ISL
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_L_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.ISL
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=M
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.NLD
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_M_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.NLD
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=N
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.NOR
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_N_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.NOR
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=O
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.SVE
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_O_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.SVE
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Compiler Variable If
+  Variable=_LANG_LIST_
+  Value=P
+  Flags=00000010
+end
+item: Compiler Variable If
+  Value=%_WISE_%\LANGUAGE\UNWISE.JPN
+  Flags=00000011
+end
+item: If/While Statement
+  Variable=LANG
+  Value=%_LANG_P_NAME_%
+end
+item: Install File
+  Source=%_WISE_%\LANGUAGE\UNWISE.JPN
+  Destination=%UNINSTALL_LANG%
+  Flags=0000000000000010
+end
+item: End Block
+end
+item: Compiler Variable End
+end
+item: Compiler Variable End
+end
+item: Remark
+end
+item: Remark
+  Text=     Install the add/remove or uninstall icon
+end
+item: Remark
+end
+item: Set Variable
+  Variable=UNINSTALL_PATH
+  Value=%UNINSTALL_PATH%
+  Flags=00010100
+end
+item: Set Variable
+  Variable=INST_LOG_PATH
+  Value=%_LOGFILE_PATH_%
+  Flags=00010100
+end
+item: Check Configuration
+  Flags=10111011
+end
+item: If/While Statement
+  Variable=DOADMIN
+  Value=1
+end
+item: Remark
+  Text=Write uninstall info under HKLM.  This if/else/end block added by Tim.
+end
+item: Edit Registry
+  Total Keys=1
+  Key=Software\Microsoft\Windows\CurrentVersion\Uninstall\%APPTITLE%
+  New Value=%APPTITLE%
+  Value Name=DisplayName
+  Root=2
+end
+item: Edit Registry
+  Total Keys=1
+  Key=Software\Microsoft\Windows\CurrentVersion\Uninstall\%APPTITLE%
+  New Value=%UNINSTALL_PATH% %INST_LOG_PATH%
+  New Value=
+  Value Name=UninstallString
+  Root=2
+end
+item: Else Statement
+end
+item: Remark
+  Text=The same, but write under HKCU instead.
+end
+item: Edit Registry
+  Total Keys=1
+  Key=Software\Microsoft\Windows\CurrentVersion\Uninstall\%APPTITLE%
+  New Value=%APPTITLE%
+  Value Name=DisplayName
+  Root=1
+end
+item: Edit Registry
+  Total Keys=1
+  Key=Software\Microsoft\Windows\CurrentVersion\Uninstall\%APPTITLE%
+  New Value=%UNINSTALL_PATH% %INST_LOG_PATH%
+  New Value=
+  Value Name=UninstallString
+  Root=1
+end
+item: End Block
+end
+item: Else Statement
+end
+item: Add ProgMan Icon
+  Group=%GROUP%
+  Icon Name=Uninstall %APPTITLE%
+  Command Line=%UNINSTALL_PATH% %INST_LOG_PATH%
+end
+item: End Block
+end
+item: Check Configuration
+  Flags=11110010
+end
+item: If/While Statement
+  Variable=DOBRAND
+  Value=1
+end
+item: Edit Registry
+  Total Keys=2
+  item: Key
+    Key=Software\Microsoft\Windows\CurrentVersion\Uninstall\%APPTITLE%
+    New Value=%COMPANY%
+    Value Name=RegCompany
+    Root=2
+  end
+  item: Key
+    Key=Software\Microsoft\Windows\CurrentVersion\Uninstall\%APPTITLE%
+    New Value=%NAME%
+    Value Name=RegOwner
+    Root=2
+  end
+end
+item: End Block
+end
+item: End Block
+end