While making phpBB3 and IntegraMOD cPAddons ive run into a small issue. In order to install the db im using the normal [% username %] tag, however phpBB3 requires another tag that does not exist. It needs something like this. [% username_clean %] . This tag is essentially the same as the username, but it is lowercase. Im sure I can accomplish this using preg_ or str_replace , but where are these tags defined, and what is the easiest way to go about this?