You can try the Blackberry development forum here (run by RIM): BlackBerry Support Community Forums - BlackBerry Support Community Forums
This is not official support, but it is monitored by RIM folks.
Also, I seem to recall there is a bug in 4.5 where a module, not actually needing the RRT signature, complains after loading on the device that it is not signed. AS I recall, there is a way to force the RRT signature to be applied (even though the module does not need it).
One thing you might try is to actually reference one of the secure API's within the offending module to force the RRT signature to be applied.