[jQuery] How to add a background graphic to the top-level menu item?

[Jeremy]

Love the menus.

I would like to re-style the top-level menu items to use a background
graphic.  I need to provide 2 elements - each one specifying a
different 'background-position'.  Eg

                                <a href="#a" class="jc-tab-right">
                                        <em class="jc-tab-left">
                                                <span>Home</span>
                                        </em>
                                </a>

Any ideas?

Thanks
Jeremy