After successful slipstreaming all updates for the Forefront TMG installation media I tried to duplicate the success for the Forefront TMG Client installer, which lacks update KB2616324.
I failed to slipstream this update, although it looks like it is going fine, the installer is not updated. After running the “updated” installer it still installs as 7.0.7734.100 instead of 7.0.7734.186.
I checked the patch file with Orca, and it looks all OK but doesn’t seem to work out. Applying the update to a system with the Forefront TMG Client installed, works as expected. Will need to deploy this update after Forefront TMG Client deployment.