Yamaha DTXpress/DTXplorer/DTXtreme

I have a DTExpress 2 and the manula talks about having the abililty to
record up to 32 songs ..which is simple enough to understand. Plya
along and record ...
What the manual does not seem clear about is this - Can I take a piece
of a song ( in wave file format - or other format ) and have it
transfred off my PC,  stored,  and then play in the module ? Dose it
have to be in midi format on the PXC to transfer to the Module ?
What I would like to do is have small intro parts of songs that I can
use in the DTExpress...its just a matter of what format the module can
support.  ie only midi ?

Thanks
Grant