ps switching for the aux input requires ideally a remote source selector (usually electronic).

check out something like:

http://www.shoptronics.com/jeksmumoauvi.html




I'm not a big Jensen fan, but other brands exist.......

you connect the output from this to the aux in, and the inputs from other sources (independent XM, Ipod, Sirius, Carputer, etc) to this, and use the remote to switch between sources......