Hello Dan, I may be able to help.
I have an Epson scanner & the software I use (I'm at work just now, doing an evening shift & can't remember the soft wares name) has a preview & a scan button.
Pressing the preview gives just that & then using the mouse or graphics pen as I have I then click & drag an 'ant line' (moving dashes) around the image which crops out the surrounding white & then I press scan & it just scans the image.
Then it opens a dialogue window asking what format to save in & to where etc.
o here to download the software,
o here to have a basic lesson on it,
Sorry if this reply is too late but I only joined today, 9th April 2014.
I'll post back later with the software name but it definitely is an Epson programme so if your scanner is an Epson it should work. Simon...