"Earlier this year, Palm began releasing Treo smartphones that run on Windows Mobile (such as the Treo 700w and Treo 700wx) with integrated drivers that support their SD Wi-Fi card. So if you own a Treo 700w/wx, this feature can now be yours with Palm’s SD Wi-Fi card."
From MyTreo.net review - November 7, 2006 11:41 PM

So, it's not a hardware limitation... What's their excuse for not working on Palm Treos? ....cough-- cough... oh ya Carrier would rather sell internet..