As you've noted, the only way you'll be able to complete this task is if you tap into the power of custom items. Custom items will have the ability to execute this task quite well. First, I would recommend you start off by trying to understand how the software's custom item samples work:
http://www.empirisoft.com/medialab/h...stom_items.htm

Next, I would recommend you see the following link:
http://www.empirisoft.com/support/showthread.php?t=1315

In the above link you can find resources that are already made available to help you with this task. For the most part, you may end up having to do a smaller portion of work (than originally perceived) to get your experiment up and running exactly as you want it.

If you need further help, feel free to ask. I would be glad to help get this experiment up and running.

Regards,
Trevor

Edit: (Also check out the sharing forum: http://www.empirisoft.com/Support/forumdisplay.php?f=25)