Did you ever get yor passthru to work? I just got the same one you did from MV.... and I have a 901/808 adapter for it that I use. The 901 atty and cart works, but none of my 510 or 808's will. I even tried backing it off and even lifting the pin at the head of the atty up some..nothing will work and at least I can use the 901 atty and use it but nothing else will work with it though. Was hoping you found out something that worked.