Herb - as John has said use MakeHex. That's what I did, I made codes for device 2 and functions 0 to 127. You won't need that many functions for the PTAE900. I then used Hex2CCF to create panels which I could alias my buttons to.

Ed - as you have said the IR232 won't help you with most devices. I really wish my PJ had an RS232 port (which I could control using the PLC and IR232) as since adding my anamorphic lens (I run a constant height 2.35:1 set-up) the IR receiver on the PJ is obscured by the lens some times and I really have to point my pronto at it and press the buttons several times to make it respond!