mens slow-pitch softball

Question
I have been in a washington, dc men's slow-pitch league for over 2 years.  I usually pitch and have always pitched with a backhanded motion (palm over the ball) that puts backspin on the ball.  We have had the same umpire the entire time and he has never called the pitch illegal.  We recently played a new team that told the umpire the pitch was illegal.  The umpire immediately told me I was "hiding" the ball and I could not pitch backhanded anymore.  He called every backhanded pitch illegal and awarded a ball.  

It looks like the ASA code says the pitcher can pitch with his palm over or under the ball.  Is there any way my pitch could be illegal?  And if it is legal, how do I get the umpire to allow it?

Thanks for your help

Answer
Hi SB,

You know sometimes I wonder, I just wonder....where they get this stuff.

In sp the pitcher is 50' away, must deliver the ball at moderate speed between 6-12', the ball is in the air 2.5-4 secs and you're hiding the ball by putting your palm over the ball???????????

This is a legal pitch!

Memorize this...pg 94, 2007 ASA rule book, Rule 6-3-d ...."the palm of the hand may be over or under the ball."

If an umpire that doesn't know the rule book, calls it illegal, give them the above and if they continue to call it illegal protest the game as a misinterpreting of the playing rules.  I would continue to pitch that way, let them call every pitch illegal so their UIC can see to it they put qualified umpires on the field.

Mark