U.S. Divers perscription mask leaks under nose!

[darsunt]

I recently purchased a U.S. Divers mask. It is specialized for prescription lenses. I've tried different ways of wearing it, but in 2 dives it persistently leaks under the nose, most annoying. I dive holding the nose pinched with one hand.
I have not had this problem with other, cheaper diving masks. Have any of you had this problem with U.S. Divers masks? I plan to take the mask back to sports chalet, what should I ask them to do?

Thanks

 

[BRT]

One of my buddies got a new prescription mask that leaked. It was coming around one of the lenses. I took it apart and put a little silicone grease around the lens and it sealed right up.

 

[tech_diver]

You can test the integrity of the mask seals by doing a reverse-face-suck test. Put a dribble of water in the mask, then suck it to your face while face down. Tilt your head around so the dribble of water moves around the seals (where skirt meets frame and glass meets skirt.) It'll start bubbling when it passes over the leak. This will help confirm the existence and location of the leak.