Uninstalling a 64-bit application using SCCM

I have a script that uninstalls applications from x86 and x64 systems using the syntax of msiexec.exe /x {app_guid}.  The script works perfectly when run manually on any system and from SCCM on x86 systems.  However, when run on x64 systems from SCCM, the uninstall returns a 1605 message which corresponds to 'This action is only valid for products that are currently installed.'  The applications that I am trying to uninstall are 64-bit and could correspond to one of many GUIDs depending on their version.
 
I know that SCCM is a 32-bit client, so I've tried various workarounds including using a task sequence with 'Disable 64-bit file system redirection' set, but the uninstall still fails with the 1605 error.  Using the %systemroot%\sysnative folder isn't an option since we are still mostly Server 2003 and the required hotfix to support the redirection isn't installed.  Pushing the hotfix is a non-starter due to the reboot requirement.
 
Any other suggestions on how to uninstall the 64-bit app using SCCM?
 
Thanks