ImageService: Equivalent of "Display Background Value:(R,G,B)"

[LanceCrumbliss]

i have two image services, one on top of the other.  the topmost image service contains white blocks around the edge and obscures the image service on bottom in these area.  what is the ESRI silverlight API equivalent of "Display Background Value:(R,G,B)" so that i can set the value of 255,255,255 in the topmost image service layer to null?  It's set to image format: PNG8, already.

lance

[dotMorten_esri]

You should set this in the MXD used in the service. There isn't anything like this in the API.
You could use a pixelshader on the Layer.Effect property that does this, but the performance isn't always great when using effects on the layers. You can read about one of these here: http://blogs.msdn.com/b/synergist/archive/2009/05/14/alpha-video-with-silverlight-3-pixel-shaders.as...

[LanceCrumbliss]

You should set this in the MXD used in the service. There isn't anything like this in the API.
You could use a pixelshader on the Layer.Effect property that does this, but the performance isn't always great when using effects on the layers. You can read about one of these here: http://blogs.msdn.com/b/synergist/archive/2009/05/14/alpha-video-with-silverlight-3-pixel-shaders.as...

optimized map services can't have an image service layer, so setting it in the mxd file wont work.

i'm a little surprised there is nothing in the API that would allow for this functionality though.  is it planned?