I have, er, no idea. I just put in that using the form-button and attached the macro to it. If you open the powerpoint file in edit mode.. and you double click the excel table, then you can actually click the button. But in slideshow mode, I cannot.

Creating a macro inside powerpoint and linking it to a mouseover/click action is preferable, but I have no idea how to find out the address of cells in the embeded excel table!