2012EdgeOwner

Just received new 2012 Edge. Does not have Sirius satellite radio but the head unit is "Sirius ready". Best Buy says they can install it but I have to purchase the tuner from Ford 1st. I've called the parts department at 2 different Ford dealers but they seem to be clueless. Does anyone on this forum know what I need to order? I'm sure I can install it myself, I just need to get the right part. Thanks in advance, S