Broadband Wireless connection

I’m from Madagascar and I need help with my Internet connection. I can’t get access to the Net with linux and I’m using a Broadband Wireless connection (I’m linked with my ISP with antenna.)

Parameters are correct (IP, Mask, DNS) and network cards are detected and working,

But connection doesn’t work with any linux distros (FC2, KNOPPIX, Mandriva, etc.) ; with windows XP, there’s no problem.

Thanx for your help !