Just create a non-locked sub-forum to post in? Any time you make a post, an account is created for the username you used.

Another thing you can try is to remove `&& !isset ($_SERVER['PHP_AUTH_USER']) ` from line 196 of `start.php`, making it:

%
        if (FORUM_NEWBIES && !file_exists ($user))
%

Then you should be able to create accounts just by logging in to the locked forum. Though I have never tested what impact that may have.