I created a map using Kernel Density, then Raster clip to the city boundaries. I added 50% transparency to the layer in the MXD. When I publish and add to the webapp as a Dynamic map service (10.2), instead of transparency I get a heat map with all the 'NoData' area colored grey, and the map service layer iscompletely covering the underlying features with no transparency.
How can I get transparency with this layer?