Plugin Variable Not Displaying

[FireFeather]

I've been searching for a solution for this for several hours and I haven't been able to resolve my issue though I've implemented exactly as quite a few tutorials have shown.

I'm trying to include a PHP file (ultimately) in the header, but have simplified the process just to test the variables at this time.
I've created a new plug in with the follow fields set:

Product: vBulletin
Hook Location: global_start
Title: Include CC Site Banner/Menu
Execution Order: 1
Plugin PHP Code:
ob_start();
include(DIR.'/../library/header.php');
$includedphp = ob_get_contents();
ob_end_clean();
$includedphp = 'julie is testing the header';
vB_Template:reRegister('header',array('includedp hp ' => $includedphp));
Plugin is Active: Yes

In the "header" template, at the very top, I have added:
{vb:raw includedphp} testing

The location of this forum is at:
http://www.centercross.com/forum/
I can view the "testing" output that was put into the header template directly, but I cannot for the life of me get the "julie is testing the header" to appear before it.

Any suggestions anyone has would be greatly appreciated.

-Julie
Texas

--------------- Added [DATE]1310601479[/DATE] at [TIME]1310601479[/TIME] ---------------

Also, as a side note, the master plugin system is indeed turned on:
Enable Plugin/Hook System: Yes