   Multisampled Depth Buffer to NonMultisampled
  I have a pass where I render the bright areas to a texture for bloom effect.  Right now I am only blooming the sun.  When I do this pass, I want to use the current depth buffer because it has all the scene depth information, so that the sun is not rendered into parts where it is occluded.  The problem happens if multisampling is enabled, I need a nonmultisampled depth buffer for rendering to a texture (DX9).  Is there a way to copy from a multisampled depth buffer to a nonmultisampled?  I can't tell if StretchRect will work or not.  It says "Format conversion, stretching, and shrinking are not supported." for depth/stencil buffers, so it sounds like it won't.Any solutions other than rerendering depth?   