Last modified date

Hey,

Im working on a project where files are being loaded using the URLloader in flash as3. I need to be able to find the last modified date of the file that is being loaded, unfortunately the files may not always be on the same server as the flash app, so it may not always be possible for me to add a line to the file that has the last modified date, that could be read easily in flash. I was wondering if anyone knew of a way to retreive this information, I know in air you can use URLLoader.httpResponseStatus which allows you to get the http headers and find it that way but it doesnt appear to work in flash. Any help would be great, Id like to try to do this with out having to call on javascript or php to find it, since it would then require 2 connections per file i believe to be able to do everything I need 1 to get contents in flash, and one for either javascript or php to find the last modified date, but if I have to that seems to be the only option I can come up with. I dont maybe Im thinking about this all wrong. thanks in advance.