In Slackware there is a posibility to use a Intellimouse on both PS2 and Serial port. I haven't use Mandrake before, but I heard it is a Red Hat like distribution. If so then you can configure your mouse from the Main Menu. There is an application that does this, I can't remember it's name exactly but I remember it was found somewhere in the system group and it had a very suggestive name, something like Mouse Preferences or Mouse Settings.
Try finding this application. I'm sorry I can't help you more.
You can also set your mouse pointer by manually editing your XF86Config file. For example: my mouse has a scrolling button for the internet. But it is a PS2 mouse which isn't listed in the xfree86 driver list. So I load a simple PS2 mouse and I added the line
Option ZAxisMapping "4 5"
By doing this, my optical PS2 Samsung mouse is fully operational even if it doesn't run on its own driver. Some option must exist for your buttons also but I don't know them all. Try finding information about Options passed to the mouse driver in XF86Config file on the Internet.
Hope I at least gave you some usefull pointers.