Ubec / Evx

hate to bring up an old topic but i have a question. i have a stock e-maxx running spc 7 cell batts and a evx. i recently bought a hitec 645mg servo and it performs like doodoo and causes major glitching and the only cure to that is to remove the bec and use an rxpack, but i dont have room on my chassis and thats just one more thing i need to charge. so can i wire a ubec some way as my esc does get hot and i cant run 6 cells on one side and 8 on the other as my charger limits to 7 cels a pack. so any help would be great. and the servo works great in my savy an preforms flawlessly with bigger tires. thanks again
BL_maxx