CSS Styles on the drop down menu?

Hi,
I know there have been a few posts about CSS styles.
I have linked to my CSS styles so I can display the pages as they should be in FCK (i.e. with their actual, preassigned styles such as background colours, showing). But I can't populate the styles drop down menu with them. This is vital for me so that I can allow my client to format his text properly.
How would I go about being able to select CSS styles to apply them to highlighted Text?

I have the following which allows the current state above:

FCKConfig.EditorAreaCSS = 'http://www.mydomain.com/styles.css' ;

Some help would be much appreciated.
Thanks
Tom