Hi Steve,
I think you should set the connection in e.g. 2 as SAT (STB) and then the list is on. You choose the SKY+ device.
All these of course assuming that you have a SKY+ decoder connected in SCART 2, your scart cable is ok (too many problems with scart cables) and of course you also have connected the ir repeater cable from the AVANT to the decoder.
Hope this works or helps in any case.
Best regards
Spiros