Linking Combo Box and List component to output data

[kerouac9]

I have set up a prototype course factsheet for my college which basically feeds information from an XML document into dynamic text fields depending on the users selection from the combo box component.

Its all working well but here comes the problem; as there are over 300 courses I dont want the user to have to scroll through all of them in the combo box. Eventually, Id like to get the user to select a subject area (i.e.Science) then the list component to be populated with all relevant courses. Lastly the user could select an individual course which would then load the data from the XML feed.

I have tried it numerous times and have successfully got the combo box and List to work but it doesnt seem to be displaying the end data if I flick between different courses. Should I add a submit button to initiate the data feed or would there be a more useful component to use rather than a List.

Any help would be greatly appreciated, I have checked out Macromedias forums and although they offer tutorials on more simplified component binding I cant seem to work this one out.