So why when you set it to "false" it doesn't seem to take effect?

This wasn't easy to guess... and this property is new in Beta 2 so not so much "discussion" on the web about it. After few hours stolen from my sleep time, I've found that the BeginGetResponse callback parameter will be called only when you'll have at least 4kb "buffered"... (is this "by design"?)...after 4kb of data received, you can receive a single byte at a time if you need to!

Look at my post on Silverlight forum for more details.

Update: This problem is specific to IE. It works in Firefox... but I have found another issue with Firefox; if you set a custom header webrequest.Headers["custom"]="custom" , AllowReadStreamBuffering won't work.... no effect... it will wait until the stream is all arrived.

In last my post about "Silverlight Project Structure" in Visual Studio, I talked about how Jose Fajardo was defining his project's structure and how it seems being a good approach. One problem, as Jose mentioned, was that "templates" edition weren't supported by VS-Blend combo. The solution was just to create a regular UserControl (so editable in Blend) and copy&paste the content in the app.xaml TemplateControl section (considering a "global" template).

If you got it right-on, that was good but after few copy&paste it became annoying. I was tired of editing my templates manually... manually as in "edit UserControl in Blend, open app.xaml, copy & paste UserControl code into the the TemplateControl section".

So I've started "googling" on "Visual Studio addon"... and it pointed me to the Visual Studio Extensibilty (VSX) web site... I've downloaded the SDK, tried the "wizard" project, modified it here and there, done some tests...

I ended up with a nice addon that converts my UserControl to TemplateControl by right-clicking my XAML file. Wow, that was much more effecient then a copy&paste...

All this to say that I was going to publish in more details my VS addon code and description project but after the last byte of Expression Blend 2.5 June Preview and Silverlight 2 Beta 2 releases, it's now irrelevant...