What hook/file is used just before the vbulletin page is displayed?

[workplaybiz]

I am working on a modification and I have a quick question -
What hook/file is used just before the vbulletin page is displayed?

I am looking to add a line of php code to the end of every outputted template before it is displayed to the user.

I have looked through the code and I have come up with:
eval('print_output("' . fetch_template('TEMPLATENAME') . '");');
as the line that outputs the template.

It would be ideal if I could create a plugin to do this.

Thanks,
John

--------------- Added [DATE]1206227479[/DATE] at [TIME]1206227479[/TIME] ---------------

I am trying to use IonCube's HTML encoder (http://www.ioncube.com/html_encoder.php) to encode outputted files.