How to interface the transponder and HSI selectors etc ?

Hi.

Can anybody please tell me how to get the transponder switch (Off, STBY, ON, ALT) interfaced. Or any switch for that matter that is NOT listed in the FSUIPC list of assignments. I use a GF-45 to dial the XPNDR code but I need to operated the actual XPNDR selector as well.

I use the Hangstrom USB-108 and have successfully used a rotary switch to assign each position on the XPDR. However I can't find the corresponding assignments (the commands) for the XPNDR. I also would like to interface my other rotaries to switches like the HSI Range, HSI selector, TCAS selector etc that are featured in Level-D 767, but again I can't find their assignments/shortcuts anywhere either in FSUIPC or in the FSX key/button lists.

Cheers,
Nick