To me, HSPA VoIP = Phone. What's there to hack? The problem is not whether you can get your HSPA chip to serve you some proprietary 3G format (rather than TCP/IP), but whether you can use VoIP without it being blocked by your jealous telco ISP and without incurring extra data charges because you go over your limit... Trying to get a data HSPA chip to act like a voice chip seems as silly as converting your 4WD off-road vehicle to run on railway lines. Why would you lock yourself into that narrow little track when you've got something that can take you anywhere?