help with multimedia iphone4 snap in adaptor

[Grantsmith82]

hi
my dad has a 2010 bmw x1 with idrive system
hes just got himself a iphone4 multimedia snap in adaptor to replace the 3gs adaptor he got the multimedia one over the basic so he can play his music.

however hes struggling to get the music to play. on the 3gs adaptor if he played music it would play out of the iphone speakers hes put the new adaptor in with his iphone4 and playing music but no sound so can someone help with the menu on the idrive where he needs to navigate to to get the music to play..

thanks