USB Modem Lock-in: The Reason to buy a 3rd party 3G USB modem

What happens when you put a DST SIM card into a b-mobiled branded TechFaith Flying Angel 46 USB 3G modem as shown below?

You get a bunch of fail as the modem is locked. This is a reason to buy a 3rd party 3G USB modem as it should support any SIM card and thus will be useful for bringing overseas as well. I contacted b-mobile who told me to contact the manufacturer. I tried to email but did not get any response from them. Perhaps it’s round 2 for trying to contact them or try to learn the inner workings for locking and unlocking modems.