G'day Giorgio.I see your problem. Any decent pressure on the lever will distort the mounting. That would bug me too.Have a look here for a list of suppliers members have been happy with.http://www.a7a10.net/forum/index.php?topic=2494.0When you contact them explain the problem to them. The picture is worth a thousand words when your native language is not English.(yours is very good)Cheers