A little late to weigh in on this one but just for posterity;

It is possible to run a signal from say a phone headphone jack etc. direct into the tuner through the antenna port. I.e. direct soldering a line through. However, it definitely is dubious at best. First of all you have to take some of the power out with a resistor of sorts. I'm not exactly sure what as I've never actually done it personally, but could be done. You will however likely get mono from the tuner.
The way it works is basically a tuner, regardless of mode or band it's tuning from is just looking for anything operating at that band to amplify. A line signal from an ipod or the like will come through at a very strong signal on pretty much anything you tune to.

Anyway, just something that can be done.