BufferingTime Breaks Blend...

Ok, So Silverlight 1.0 is supposed to be out in the wild now and Expression Blend is like the coolest tool available for working with Silverlight Xaml especially if your a designer it gives you WYSIWYG and code. But alas having all of Silverlight actually not break Blend appears to be a bit unreasonable of an expectation still... not that I'm whinning but it seems that on a media element if you try to set the 'BufferingTime' property Blend will puke. According to the documentation this is defaulted to 5 seconds and the Silverlight Teams says that Silverlight try's to make an intelligent decision about this but if you actually try to tweak it your self as per the documentation it doesn't seem to do anything and blend blows up...