You can only do it by editing the registry. There's an article in the MS knowledge base that explains how to do it. Check out
http://support.microsoft.com/support/kb/articles/q165/6/40.asp?FR=0.
>I read somewhere that it was possible to change the default comment indicator *!* when commenting text using the option under the format menu. Could somebody point me to it please?. I am doing a major revision to code written by somebody else and I would find useful to be able to comment portions of text with say, my initials and a date.