I have pretty much the same scanner and the 
scanning software--intelliscan or something--
automatically crops off the white areas.  The 
only thing I've found to counteract that "feature"
is to actually put something like an envelope
at either end of the thing you're scanning so
the software "sees" it and then you can crop it
yourself in your preferred image editing software.
I hope this helps you out! :)

Jen