Does anyone know how to add additional browser specific stylesheets to apply to my zencart store?

I'm trying to fix a positioning error that only applies to IE6. Normally I would create an additional stylesheet with the adjusted positioning just for IE6 and then add the following code in to the HEAD of my page...

<!--[if IE 6]>
<link rel="stylesheet" type="text/css" href="css/screen_ie.css" />
<![endif]-->

Trouble I'm having is I dont know where to place the <!--[if IE 6]> code so that its then placed in the HEAD area of all my zen cart pages.

Any help would be great.