Two combobox with webservice - help


I would like to create a flash-application that works like this example:

Combobox1 provide some country names
Combobox2 provide some city names

The data should be provided with webservices (like .asmx).

I want them to work together and when i choose country in Combobox1 all cities related to that country will be shown on the second Combobox2.

I’ve searched alot for an answer but couldn’t find any for AS2 and please now i need your support. Any help with this would be very kind. Maybe someone has an source-example with something like this or close to this.

How do I make this??

If possible an example of the webservices would be cool too but not necessary.

Thank you alot