Need help with preg_match plugin

[unitedpunjab]

This works in "postbit_display_start" hook, "$test" returns da value I want but only in "postbit" template.

How do i get the value in headinclude or showthread template ?

PHP Code:

$fost = $this->post['pagetext'];
if (preg_match( '/youtube.com\/watch\?v=([^"]+)\[/', $fost , $match ))
        {
        $test = $match[1];
        } 


Edit: this worked

$find = '$YTIMG';
$vbulletin->templatecache['SHOWTHREAD'] = str_replace($find, $ytimg, $vbulletin->templatecache['SHOWTHREAD']);