the easiest way that i have found to get around this is to have seperate XML documents that provide each language string. depending on the language initialisation load the different xml file, xml_en.xml/xml_fr.xml etc... then the rest of the program is completely the same and the system is completely expandable if you need to add more later.
these files can either be loaded externally or embedded in the swf file for ease of transportation.
i always ran the language setup by passing a flashvar from the loading page. do you have access to the hoasting page?