Ok, with Nexuiz.exe all my mouse buttons work however it is a little slower than SDL and the sound has no positioning at all.
With Nexuiz SDL mouse 4 and 5 do not work but the sound is much more positioned (you can tell where sounds come from) and it runs faster.
So, either I play with reduced speed and sound with no positioning
Or I play without the use of my mouse 4 and 5 (both of which I have weapons bound to) and have better fps and good sound.
This is a problem. Either nexuiz.exe needs to have the sound system of sdl implemented and have the speed tweaked, or the sdl version needs to be fixed so mouse buttons 4 and 5 work.