Forcing a Style depending on the clients USER_AGENT

[DeMiNe0]

I play a game called EVE Online. In this game their is a Browser that players can use to view web pages. This browser is not capable of rendering graphics, java, or any css thats complex. Infact here is the documents and development notes for anyone interested in this small in game browser:
http://bughunters.addix.net/igbtest/
http://bughunters.addix.net/igbtest/IGB-commands.html

I run a website that many EVE Online players visit. I would LOVE to be able to have players visit the site in the ingame browser, but the problem is the in game browser won't render the pages of my vbulletin theme. So i've been trying to figure out a way to have a certain style displayed when the HTTP_USER_AGENT is the agent of the in game browser...

I have the following code in a GLOBAL_START plugin, but it doesn't seem to be working. Do any of you guys have any idea why it won't work?

if(strpos($_SERVER['HTTP_USER_AGENT'], 'EVE-minibrowser') !== false) {
$styleid = "2";
};