Borderlands (Steam Version) On a Mac Mouse Problems

["iNom" <wineforum-user@xxxxxxxxxx>]

I can get into everything and the menu, character selection screen, and all of that works just fine; but when the cursor is no longer visible and I start the actual game, my sensitivity is so ridiculously high, it's either facing the sky or at the ground, no matter how slightly I move the mouse.  I tried changing the in-game sensitivity, and I have no idea how to fix this.
Any suggestions?