making Flash talk to PHP

I know this is more Flash than PHP, but the FLash kids see PHP and stop reading and I really need help.

I'm working on making a Flash MX form pass variables to PHP. All is working with the notable exception of combo boxes. On suggestion from a Flash coder, I used var_str = comboinstance.selectedItem in the click event of the Flash submit button but that is passing an object. I think the parameters in Flash are set wrong, but I don't know what they should be.

The parameters for the combo box in Flash are set as:
labels = [Entire Bridal Party, Bride and Groom Only]
data = [Entire Bridal Party, Bride and Groom Only]
editable = false
label count = 2
enabled= True
visible = True


Please, the client is up my rectum on this and I'm stumped. Thanks.