How to add a tier that slides out in an AJAX vertical accordion menu

Hi,
I have gotten a very good Vertical accordion menu for use from Dynamic Drive @ Urban Gray Accordion Menu

I am new to AJAX scripting and I would like to add a sliding panel to the right when a user mouse overs the pointer on the child menus that appear below the menu headers like in the image above.

I would like some help to tweak the code.

Thanks in advance.