For example in Sketchflow add-in there is ApplicationFlowPane (derrived from PrototypingPane) which registers itself using IWindowService like this:

    service.RegisterPalette(this.PaletteRegistryName, this, this.Caption, this.KeyBinding);  

But i can't see where it is defined that it is docked on bottom pane.
Before someone replies that it's at:
%AppData%\Microsoft\Expression\Blend3\Workspaces
No it's not there because those files do not exists at first run.

The question is how can i put my window at certain position with Expression Blend 3 plug-in api ?

update 1:

It seems that to achive what i want i have to change design.xaml (where workspaces are defined) which is loaded from satellite assembly Microsoft.Expression.Blend.resources.dll (method load in class FrameworkPackage in Microsoft.Expression.Blend.dll). But since this dll is strongly named i can't change it.

So now the question is. Is there any other way I can change Design Workspace at runtime ?