Adding additional parameters to SWFUpload

I'm trying to add an extra message parameter for every file uploaded with addFileParam

, the documentation explains itself pretty well, but when I try to add anything it adds a value to the size parameter, causing it to do something like this

SWF DEBUG:   'Filename' => 'image.jpeg',
SWF DEBUG:   'cnid' => 'up5121fcacd30besize=539321',
SWF DEBUG:   'Upload' => 'Submit Query',

      

        
        
        
      

    

When I really need this:

SWF DEBUG:   'Filename' => 'image.jpeg',
SWF DEBUG:   'cnid' => 'up5121fcacd30be',
SWF DEBUG:   'size' => '539321',
SWF DEBUG:   'Upload' => 'Submit Query',

      

        
        
        
      

    

My Javascript:

function onQueued(obj) {
    swfu.addFileParam(obj.id, 'cnid', 'up5121fcacd30be');
    swfu.startUpload();
}

      

        
        
        
      

    

Any idea what I might be doing wrong? I've tried wrapping the value for example, '"'

and I've also tried semi-columns at the end. I am using the Yelp version of swfupload as it seems to be the most recent.