Ok, I want to do something oh, so, simple but VBulletin is having none of it

God damn American software...
Here's the deal... On my site I have a single header file called 'head.php'. On any page on my site which I want to use the same header, I just wham in
PHP Code:
include ('head.php');
..And it spits out a lovely pre-formatted header with lots of 'Welcome to my Website' stuff, the navbar, etc.
Including it as a hook means it works, but, it's all spitted out at the start of the page, ie you have a situation like this:
Code:
<table>
welcome to my website
</table>
<head>
Which is completely nuts from a HTML perspective
How the hell do I get VBulletin to run my 'head.php' file
just before the rest of the forum content (exactly where the default VBulletin logo would go?)
All help and suggestions much appreciated!
PS. Can't edit the head.php file because it's integrated into about 453 files on my actual website, and I can't just cut & paste the HTML/PHP into VBulletin because it changes alllll the time..