iSimple iPod adapter - XM not working - Does yours?

[Playu18]

Hello,

I am wondering if any of you use the iSimple iPod adapter in your Muranos, and still have use of the stock XM radio? I purchased my iSimple a couple of years ago and hooked it up, and everything seemed to be working just fine, but I never checked the XM function until recently because I wasn't a subscriber. It didn't work, but I honestly just figured I had missed a wire or something, so I let it be. Recently I upgraded my iSimple unit to accommodate my iPhone 4, and after re-installing it, the stock XM feature still isn't working. I guess I am wondering if it is supposed to? In reading up on the iSimple units, it seems everything I read says that I should still have XM functionality. Oh, and I have a 2007 SL with Nav.

Thanks for any help/input you can provide.