Disregard my last post. I figured out the problem. The rotatory switch on the front of the URTSI-II needs to be set at 1, otherwise the RS-232 does not work. I set it to 1, now I can successfully control all of my window shades through the Roomie app!
Glad to hear you figured it out 
Thanks, rjdevries. Yes, it was actually easier than I thought. I followed the steps I mentioned above.
Note to anyone looking to try this. You must pair up your URTSI-II with each of your window shade channels before you try to integrate with the Roomie. I had professionals install my Somfy shades and they provided a 5-channel Somfy remote. I bought the URTSI separately, and did a copy/paste of each channel from my remote onto my URTSI-II. Video demonstration here https://www.youtube.com/watch?v=ADse7u_3WZY is helpful. Once the URTSI can operate your shades, then set its rotary channel to 1, plug into a IP2SL or Flex with serial cable and configure it, and done.