Hey guys... I'm sorry for the (VERY) late reply, but I was just looking at this forum and saw your questions.

My workaround is that I define a RS232 device on the MSC400. Let's say it's called "PC Controller". On that device, I define functions that send ASCII commands like "AVR_VOLUP", "AVR_VOLDOWN", etc. I can use the same RS232 device for multiple devices as well by just changing the ASCII command (i.e. "HDMIMATRIX_PORT1", "AVR_VOLUP", "UPSTAIRS_LIGHTSON")

The PC (connected using RS232) receives the command and then transmits a new command using TCP/IP to whatever device I want.

The flow is like this:

1) MX-880 presses button.
2) MSC-400 receives RF signal.
3) MSC-400 transmits command to PC using RS-232.
4) PC receives command and transmits new command using TCP/IP.
4a) The PC actually parses the ASCII command (i.e. "AVR_VOLUP") so it knows which device to send to (i.e. "AVR") and what command (i.e." VOLUP").

I am really, really disappointed that URC didn't come out with any new products that incorporate this type of relay system. I completely understand why ($$$) but it's unfortunate for people with legacy equipment.