I connected a URC MX900 to a MZC66 today via a MRF350. Just connected a wire from a 1/8 jack on the MRF to the IR and GROUND terminals on one of the zones. Then, from the MZC editor software, right clicked on each button I needed to use on the MX900, and selected the last option, which is to copy the code to the clipboard in hex format. Then I opened up the mx900 editor, and pasted the hex data into the Universal Browsers Hex Editor and dragged the code up to my desired button. No learning was required and each code worked flawlessly.

This customer wanted to use the speakers in that zone for his tv, and shut off his tv speakers. So when he presses cable on his remote, it powers on the tv and cable box, and then sends the code to turn the zone on to the cable input. The volume is set for up and down on that zone, plus a mute, which is all punched through to each source. When the client hits the off button on his remote, it powers off the tv and cable, and shuts off that zone. Works great

haven't worked with RTI, but I am sure it has a way to import hex codes. Worked great for me. If you haven't already resolved all this, good luck.