It will be wired in to the tape deck, so you many need to use a pen to push the mechanism in. Will all depend on how the hack has been done. If you have a cassette, you could also take the insides out and push that in.
Sounds like someone has done this http://www.350z-uk.com/topic/45398-how-to-bose-phono-ipod-hack-guide/
You will need to follow the cable and see where it goes