IE enjoys supporting a pre 1.0 XML standard, while Mozilla only supports the 1.0 standard. Most people learned XML with all the pre 1.0 code standard, and unfortunatly quite a bit was changed in 1.0.

IE supports 1.0, so it's just a matter of getting the programmers to stop being lazy about it and learn the changes. Unfortunatly I don't have a huge grasp on XML client side yet, so I can't do much for the interface on the player. All my XML experience is on parsing it in PHP, then turning it into standard HTML for the client.