As long as all parties load the same swf from the same domain you should be good.
I set up easyXDM to load js and CSS files to my domain from an amazon S3 bucket. The loading is working perfectly, except in IE 6/7 where it relies on the swf file for x-domain messaging.Is there something that I need to set up on the S3 side or in easyXDM that would solve this for me? Has anyone had this problem?