Register in vbulletin via external page

[lkmad]

Right now the way things are set up is that you come to the website and you register for an account and as you log in with that account, it will register a forum account for you with the exact same details to save you the trouble.

Due to spambots creating accounts I want to be able to use the Human Verification which means I myself have to crack in a way the way this works. I thought of using the Question & Answer method and adding an Answer that only I would know (like an extra password) and then have the script use that.

The problem however that I am facing is this code:
<input type="text" class="bginput" name="humanverify[input]" id="humanverify" size="50" />
<input id="hash" type="hidden" name="humanverify[hash]" value="540618dd55f1489cb5365fd2248d3046" />

The way I see this working is that you answer and then the php page verifies the answer and inputs the [hash] value and finishes the registration for you? However the hash value seems to be changing each time the page loads which means that I cannot predict the actual answer.

Any ideas? Advice?