Insert CSS classes instead of embedded styles

Hi

I am trying to persuade FCKeditor to insert CSS classes instead of embedding styles.

In fckstyles.xml I have:

<Style name="Header" element="span">
<Style name="class" value="article-header" />
</Style>

and the header option appears in the styles dropdown. However, the code that is actually returned when I try and use this style is a simple <span> instead of the <span class="article-header"> I was hoping for.

Can someone help me get this working?

Cheers.