Custom Character set in header

Hey folks,

I need to set up (I think) a custom header.php loaded in a template file with a different character set in it. I need to load an old cheap shopping cart in an iframe, and it uses characterset “iso-8859-1”.

I trid it, but I guess WordPress overrides that, and just uses UFT-8 like defined in settings. So, how can I create a custom header and get WordPress read this string:

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">

I’ve done some searches but cant find anything…
Thanks.