jQuery: Dynamic change of ATTR, doesn't work with "Video JS" - by hand it does

I use Video JS to display videos, defined in an XML-document, on my site in both Flash and HTML5.

When I set the attr of a PARAM, to specify the URL of the video, it doesn't work. If I set it in the markup (without XML), 开发者_StackOverflow社区it works.

In the XML success I insert the value with the URL

$('.video-js-box object param[name=flashvars]').attr("value", 'config={"playlist":["' + image + '", {"url": "' + video + '","autoPlay":false,"autoBuffering":true}]}');

Why is this? And how do I get by this? I guess it has something to do with the similar feature "Live()", or has it?

Thank you in advance... :-)

//KennethBL