you can buy qev diaphragms and a ton of other eclipse parts from www.paintballshowcase.com
I doubt you need to though. Since it only leaks when the gripframe is mounted to the body, it means that your problem has to do with the alignment. You need to play around with the spacing of it all, making sure that the hosing and the solenoid don't get pinched or pressed at angles that will cause them to leak.
Only tighten the screws that hold your grips in enough for them to feel snug. That way the solenoid isn't pressed into an odd position that might cause leaking.