[syslog-ng] Changing replacing $Host characters

A large number of my log messages come in and the $HOST variable is an IP address. I am creating a mysql table for each unique host. The problem is, mysql does not allow table names with periods in them, or at least I can't figure out how to make it. Is there a way in the syslog-ng.conf file that I can use regexp to change 10.1.1.1 <http://10.1.1.1> to 10_1_1_1 for example? Or does anyone happen to know how to make mysql accept `10.1.1.1` as a valid table name? Thanks!