Who programmed your RadioRa2 system? They probably didn't program any of the "phantom buttons". The phantom buttons are used to generally create callable "macros" that third party control systems can utilize to perform a string of commands. So Phantom button 1 could be the scene that is called "Welcome" in your home that turns on the general lights when you come home. Rather than repeat the process on the URC side, you can just call button 1 which will perform that scene. However, none of those scenes are probably set.

Another option is to download the integration report from your configuration file and figure out the device ID's and use that for control...

If you are not the person who programmed the system you might be out of luck as RadioRa2 software is not distributed.

Good luck
Total Control Remotes