Sad it dosent work. Why dont you upgrade phone to Droid 3 stock (download unbrick Droid .bat from Droid 3 developement unbrick/root 1st post and then start from scratch like rooting , safestrap stc ) in case if u flash n if there is no signal then activate roaming. I have done d same.
That's exactly what I did; I reflashed to 5.7.906 using moto-fastboot. With the VZW radio ROM I can see the SIM MNC MCC but (of course) it won't talk GSM in the US. With the Chinese radio ROM it'll talk to the network but without data 'cos it doesn't see the MNC MCC.
The whole question is moot now 'cos I've now got an S4 and cut the SIM to size; that works just fine