The problem was that my build outputs were not being copied to the correct drop folder so I wanted to add a custom target that would do this for me. I ended up hacking the WIXSetup to call a custom target called "AfterDropBuild" that I created in my .btdfproj. I would rather not have had to hack the WIXSetup although it's not that bad because it only needs to be done once on our TFS build server. Please can you build in a target for this purpose?