Copper Pipe to Valve Leak?

I recently soldered (first time) a copper pipe to a water valve. There seems to be a pinhole leak causing water to squirt out. I tried to solder it again but the leak is in a tight area next to a cement wall.

I than tried silicon, puddy, and epoxy but they did not seem to help. (Possibly because there is water in the pipe, that cant be drained)

Any suggestions?

Jeffrey
April 2009