Argotic and YahooMediaSyndacationExtension problem (url encoded)

Question

I'm using the Argotic syndacation framework to write an RSS feed, and I've found a strange behaviour, that may be a bug.

I want to add, trough the YahooMediaSyndicationExtension, a <media:thumbnail /> tag to link a 200 pixel miniature of a certain item, and to build the miniature I used an image handler that requires the width specified on querystring.

So I use this code:

Uri imageHandler = new Uri("http://localhost/imghandler.ashx?i=image.jpg&w=200");
YahooMediaSyndicationExtension ymse = new YahooMediaSyndicationExtension();
YahooMediaThumbnail ymt = new YahooMediaThumbnail(imageHandler);

But the resulting xml has the thumbnail url encoded (&):

...

<media:thumbnail url="http://localhost/imghandler.ashx?i=image.jpg&amp;amp;w=200" />

...

and the handler can't retrieve the correct querystring parameter (w=200).

Suggestions? I'm missing something?