Anyone know how subsidy locking/unlocking works on WiMax?

Namely, I got a cheap-o Sprint Overdrive (a.k.a Sierra Wireless W801) - which Clear sells under the name "Clear Spot 4G+".

Now Sprint's monthly fees for 4G/3G mobile broadband is $60/mo with a 2 year contract. Clear is $55 with *No Contract*. Hence, I'd like to activate it on Clear.

WiMax seems to operate like Ethernet - there's a MAC ID that the carrier uses to authorize the device. But there's also a number called the "WiMax HFSN" - don't know what that is.

Since Sprint 4G *is* actually the Clear 4G network, I'm guessing this should be possible.

Any thoughts on how to do this? How do carriers network lock a WiMax device? Is there an equivalent to the CDMA MSL/SPC unlock code?