I am somewhat new to MSI and I am in over my head.

I applied a small update to an RTM installation. I have a custom action defined, and the MSIEXEC 4.5 "only run on patch uninstall" bit set and no exec conditions. I am on Server 2008, and the MSIEXEC is at 5.000.something.
When I uninstall, I get this in the log:
"Skipping action because it is not part of a patch uninstall."
Does this special CA type apply for quickpatch projects only? The patch I am rolling back is a small upgrade delivered via patch.
The only other link to this in Google is in the German MSI forum, and translations of that did not yield a useful answer for me.
Thanks In Advance,
Jesse