I just took an Escient 211 and changer out of my house. I controlled the unit with 1 way communication with an RTI T2C and never had any issues with it. I'd suggest building your own interface and control via IR.
I'm not a Pronto expert but from your post it seems you are controlling it with an IP driver. Never had any great experiences using that interface.
Diplomacy is the art of saying hire a pro without actually saying hire a pro