This is probably a generic Linux question but I can't find the answer anywhere (I've tried google, #knoppix on freenode) so would appreciate some help.
I have a Compaq wireless optical mouse with a scroll wheel which is also a push button currently bound to the Paste function (I believe that it's a more-or-less standard 5-button mouse). This button is rather sensitive and I'd like to change its binding so that it does nothing. It gets rather annoying when I'm using Kate for example and having done a cut/paste (using ^V) from one place to another and I then rapidly scroll through the text only to have the scroll button click and end up pasting what I previously copied into some random place in my code. So I just want that button to do nothing - which is what it does in Windows.
XFMouse doesn't appear to be able to do this and I've also played with xmodmap but the only docs I can find about it show how to swap the order in which the buttons are interpreted - such as flipping them for a left handed user.
How do I fix it so that the scroll button doesn't nothing at all and the other buttons stay as they are?

Best Wishes
Pete