I don't understand your configuration.
The receiver should be able to send 22khz, shouldn't it?
Doesn't the stock LNB-head have a 22khz switch to go between their two Ku birds?
I have no idea how in the menu system you activate the mode, though.
One of those $10 DBS meters with an LED for 22khz might help (?).
I'm not a real fan of loop-through operation - mostly, I see people running into troubles with it, so I look for other solutions.