Sirius Satellite Radio for 2007 Highlander Hybrid?

I've been trying to purchase a Sirius satellite receiver for my 2007 Highlander Hybrid. The dealer and Toyota said it would be available at some point and now that the '08 models have come out, they have said it will never be available. My understanding is the stereo for the 2007 Highlander is based off of the Camry, for which Sirius is available (with an extra cable). My question is does anyone know what model year of Camry is the 2007 Highlander Stereo (with navigation) based on? Toyota will not tell me.
Does anyone know if the Factory Interactive system will work for me and will this void my warranty?