JoeJoes freeware utilities has a program called rename master. It allows you to fully manipulate file names and allow you to add or deduct characters in file names.
http://www.joejoesoft.com/vcms/108/ Just let Sonar do its thing then edit after the fact, it only takes a few minutes to learn and less to use.
Sonars great with audio but it's not a file management tool. Once you use rename master you'll wonder how you did without it.