I've tested this on Windows Vista with Inkscape 0.47 r22583, built Nov 21 2009.
I draw a rectangle and then I rotate it. When I open the XML editor I see the following
matrix(0.58672135,0.61730828,-0.61730828,0.78672135,0,0).
When I export this rectangle and view it in IExplore the rectangle is not rotated.
If you look closer in the XAML with Notepad++ there is no transform or matix.
I did a manual fix in the XAML and added the following after the path.
<Canvas.RenderTransform>
<TransformGroup>
<MatrixTransform>
<MatrixTransform.Matrix>
<!--matrix(0.58672135,0.61730828,-0.61730828,0.78672135,0,0)-->
<Matrix M11="0.58672135" M12="0.61730828" M21="-0.61730828" M22="0.78672135" OffsetX="0" OffsetY="0"/>
</MatrixTransform.Matrix>
</MatrixTransform>
</TransformGroup>
</Canvas.RenderTransform>
</Canvas>
But I don't want to do this with every rotated path :-)
Fix committed in bzr revision 9396.
Also partially fixes Bug #266909 (XAML export invalid because of empty transforms).