Armen - Just wanted to point out that you posted that same question in the general Beretta area a few days ago. There were 2 answers for you. At the following link:

http://www.berettagunforum.com/viewtopic.php?t=296

There is always a way... if given enough time and money. But, there is no practical way within reason. The best you can do is a). replace the mainspring with a lighter weight spring, and b). polish the friction points lightly to smooth it out.

Wolff Gun Springs sells these springs in different weights so you can experiment. My first time polishing the sear/hammer friction points I actually made it too smooth and the single action shots were like a hair trigger. I had to replace the hammer and start over.

David Olhasso's Beretta Site