[Dovecot] scripting or translation in config

Hi Is there nay way to do translation on a char

Exp

tr ( "." ,"_",$domain)

so mysql statement can lokk some thing like this

select * uid,gid,home,.....from tr ( "." ,"_",$domain) where uid='$local' Are you ready for Telkom's 10-digit dialling? To find out how this will affect your Internet connection in the not too distant future, go to www.mweb.co.za/ten