Afaik, you either need windres, or you need a self build fpcres from trunk and pass special flags to it.
So, res files are currently part of pre-build files.
Also, sources in the IDE are set up, so they do not trigger a rebuild, but require the prebuild res.
To have them build from the rc file, find any {$R name.res} and replace it by {$R name.rc}