Well BH2372,
I checked and the servo i used is 4.8-6 volts , so your micro servo should work. Remember what i said though. I Gutted mine before i installed it so all i was left with was 3/4 of the casing, the gearing and the motor. That way i could just wire 1 wire to each lead on the motor, making it have only 2 wires coming off of it.
And as for your locking problem. I experienced the same thing when i tried to wire it to 2 buttons to make it a manually operated RF. But that was before i hooked up the rc board. After i tried ther rc board i had no problems.
Hope that helped. If you need more help continue to post and i'll do what i can to help!