The RTS app won’t work for you as you have IO devices and they are not compatible. IO is a licenced technology that has good encryption so Homey can’t talk directly to IO devices.
The Somfy Tahoma & Connexoon app (Somfy TaHoma & Connexoon App for Homey | Homey) is your best hope.
There is a topic here [APP][Cloud & Pro] Somfy Tahoma & Connexoon (v4.0.37, test v4.0.70) that might help get it working but if you have any problems with it then let me know the details and I will do my best to help.
