[1Unreal]

I did this and it worked fine

PHP Code:

$search = addslashes('<!-- / CSS Stylesheet -->');
$replace = 'foo';

$vbulletin->templatecache['headinclude'] = str_replace($search, $replace.$search, $vbulletin->templatecache['headinclude']); 


Also, how are you checking it? It wont actually edit the template. So you wont see it in the template manager. However if you view the source it will be apparent.

It has to be on global_start too. Although Im sure you have already realised that