I know this thread has been idle for a while now, but I came across some info that may be worthy of the archives.
I had problems running RR with the DigitalFX skin and having RR show the compass and speedo while getting the nav system to work. I originally had rr.ini and iGuidanceUMPS pointing to the same com port (com4). Then I installed xport3 and (here's my big mistake) set com4 to split into com10 and com11. I chose 10 and 11 just to keep things clear.
Upon starting iGuidance or iGuidanceUMPC, they immediately reset the com port in the registry to 1. This is true if it's running within rr or not. So I tried setting xport to creating ports 5 and 6 and now iGuidance does not reset the com port to 1...and everything is working!
For some reason iGuidance can only handle com ports up to a certain number.