thank you for your proposals. The main problem is the temperature range. We need -1 / +70°C at least. Both solutions (Atheros and Whiznets) don't fulifill our temperature requirement.
I tried to compile Sparklan driver for 2 USB dongles (WUBR608GN and WUBR170GN) with no success.
So if any more proposal let me know.
You can try with an Atheros wifi card, the driver is the generic one in Linux kernel 2.6.x , so you shouldn't have problems using an Atheros one.
Please let me know if you have any questions.