itouch not compatible with sound system

[bimmergirl08]

I have been using Itouch-1st generation on my BMW 5 series (2008 model with factory installed ipod hookup on Navigation screen. Last week i upgraded my itouch to 3rd generation , then my sound system is not compatible with this upgraded itouch all of a sudden, it used to navigate with radio button and hear thru speakers , now it just says it is aux instead of itouch message. And i can't play or browse thru the navigation screen any more.
itouch 3rd gen is not compatible with the Bimmer system?
please help me thank you