I have a Sierra Wireless AirCard 313U (branded AT&T USBConnect Momentum 4G USB). I am running the nanoBSD (i386) version of pfSense 2.1 BETA1 (20130104-0332) (512 MB image) on an ALIX board. With the 313U connected at boot, FreeBSD/pfsense sees the device but the u3g driver does not seem to recognize it as an AirCard. It does see the integrated flash drive that is built in to the device.
It looks like someone created a FreeBSD patch to add support for the 313U: http://www.freebsd.org/cgi/query-pr.cgi?pr=165154
I'm guessing this patch was not included in the pfSense builds for u3g? Would it be possible to add support for this device in future builds of 2.1?
If you need any additional information let me know and I can get it.
Also- thanks for creating a great product- I've been using pfSense as my home router for a long time and love it.