I recently picked up the Samsung SCH-LC11 4G mifi router with Verizon. I'm trying to use my iphone with it and run a SIP phone client in data only mode (wifi only, no cellular). None of the ones I've tried work (Softphone, Siphone, Groundwire). I believe it may be due to a NAT issue with the mifi but not sure. When I try it at home with my wifi router, it works fine. Has anyone done something similar?