Some CSS3 Not working due to CRM putting IE into Quirks Mode (IE Meta setting)

I'm trying to add some CSS3 styles to some objects in CRM 7.1h. They render perfectly in every browser except IE. IE ignores the CSS3 stuff and I think I've tracked it to the addition of this in the HTML <HEAD> section: <meta http-equiv="X-UA-Compatible" content="IE=5" />

I'm a bit shocked that CRM is being "forced" into Quirks mode with that meta tag. any ideas other than manually switching off Quirks mode to fixing my problem in IE.