Generated content with CSS + XML

Hello folks, 

I'd like to use generated content with CSS. I've read that :before and
:after pseudo-elements do it, but when I tried in IE50 it didn't work.
Like with <xsl:text> in XSLT.

I used:

HTML\:A:before { content: " -> "}



How can I use it?

Thank you

Zsolt Czinkos