tower pro servos?

[stampy]

well i got my z9000t today and ive got a problem :( . it twitches like mad. any body know why? i threw my old jr standard servo in there and its fine to twitching or nothing. im using a jr xs3 synthesized radio with a rs300 receiver to power the servo i used 2 things, i used the bec from my duratrax esc and then i used a 4 aa receiver pack (it twitched with both so i dont thing its the power source) is it maby because its digital servo on an analog receiver maby?

o and all the betteries are fresh so that shouldent be whats causing it