Getting combobox data out of a flash form via PHP

[bladey]

I have a simple 'contact details' style form in flash which has a combobox in it.

I am trying to reference the combobox data in my php script.

I have the following actionscript code refering to the combo box on the submit button of the flash form

form = new Object();
form.change = function(eventObj){
trace(eventObj.target.value);
}
combobox1.addEventListener("change", form);


//"combobox1" is the instance name of my combobox

I cant work out what to call the combo box data in my php code. The existing PHP script is a standard kind that creates an email with the users details in it and seends it to a specified address.

I have tried the following... '$change', '$form' '$combobox1(which is the instance name)' and none of them work.
Thanks for any help
m