Amir,
I think your problem with the air backing out the handle is because you are using a Silca head. They were notorious for doing just that. I've seen Silca pump handles go flying when there was a lot of presser. Get a Campagnolo head and you will not have the problem. Campy pump heads appear regularly on Ebay. Also, the correct way to remove the pump from the valve is to press it off with you thumb placed where the barrel joins the head. You can also hit it off. Close you fist and hit the pump gently at the same spot. GENTLY. I once destroyed an old-style Silca pump, the type that fits into a umbrella clip, because I was too forceful.
Good luck,
Michael Allison
New York, NY
USA