The leg which goes to the 'shell' is probably the negative lead, so you need to connect it to the ground. Connect the other lead to the middle pin of the VR.

Can you post when you have tried the booster. I'm trying to find out why there was a problem running the modded booster in the neo2, and knowing if it works in your board will help a bit . I've run simulations for the circuit and the only thing I can think of is that its some sort of protection that the neo2 has.