I can't help you with RRFusion. If you want it all contained in RoadRunner you can either:
a) use RRFusion
b) use the COM interface from MDX and embed MDX into RR like you do GPS
a is simplest, and Sonic is the guy to talk to.
If you don't have the drivers, then make sure to download the drivers.
To do relays, you need 12v power externally.