I've rebuilt my old project with your latest version 3.5.3 and have found a different behavior in subj. The Name arg now consists of your signature and my resource name, as below:
I'm not sure but AFAIR earlier this parameter was shorter and it was just my resource name like "video.flv" or "/video.flv".
Is it a bug or feature? And if it is a feature then what I might need the signature part for? AFAIK I never know what signature is for my particular swf file loaded. It's much easier to identify the control by Sender parameter.