[tjnugent]

I never got any replies, so I tried working around the limitations. Here's what I did to allow an external registration form to register users in vBulletin, in case anyone can use it.

I turned 'allow registration' back on, and then edited the navbar template so that it doesn't show the "register" link. Given that our forum URL isn't advertised outside the site, and you need to register in order to "see" them, I'm not too worried about people trying to register directly via the forums.

Then it was a relatively simple matter of making a form containing the user data (which will eventually be pulled from our custom registration page) which submits to the vB register.php page. It's important to include the "agree" variable, otherwise it will assume that you haven't yet agreed to the terms of the site.

<form action="forums/register.php" method="post">

<input type="hidden" name="do" value="addmember">
<input type="hidden" name="agree" value="1">

Also, you need to include two copies of the email and password:

<input type="text" name="email" value="email@wherever.com" readonly> <BR>
<input type="text" name="emailconfirm" value="email@wherever.com" readonly> <BR>

<input type="text" name="password" value="abcd1234" readonly> <BR>
<input type="text" name="passwordconfirm" value="abcd1234" readonly> <BR>

And of course, you can set other options, such as whether or not to receive admin emails and what the time zone offset is:

<input type="hidden" name="options[adminemail]" value="1">
<input type="hidden" name="dst" value="2">