You'll need a certain file from the Windows driver installation in order to get it work. This LQ Answer
should help you out. The writer seems to have written it for Mandriva users, but it doesn't matter, because the only distribution-specific part is the installation of XSane, which you already have. Put short, you'll need to place the .bin file (which is mentioned in the instructions) to some directory where you'll find it, preferably system-wide, then tell Sane where it is by defining the file's path in a Sane configuration file. It's not difficult, but sure is something you won't be thinking in the first place.
Chances are you can download that file from the internet these days, but I'd vote against that, because you have no way of knowing if it's the original file or if somebody has modified it. If you own the scanner driver CD, you'll find the driver (for Windows) there, and can extract the file from there one way or the other. Installing the driver through Wine is one way. Another way is to use some software that can extract that one file right out of the driver installer.
I don't own that scanner model anymore, but when I did, instructions like that were nowhere to be found
Luckily this has changed...