I use the g27, I haven't in about 4 months so I may not be correct anymore. the shifter doesn't work I think. But you need to make sure that you have rigs of rods in the Logitech profiler. Then find the key map on the software in the rigs file. Then open the configuration in the ror program and have fun. Any more help, I'll be here all day.
Ps. Rear steer with paddle shifters isn't fun, make sure you have your rotation if wheel set to about 89. That's as close as the game can get to real life.
Let me know if it works, I'm going to try this tonight. I had to wipe hdd so I lost everything when I rebuilt my PC.