In the ArcGIS 10 Plugin, even though you specify layers to be added to display in the
tab, the only layer actually added to the Table of Contents of your current map is the raw DoD raster.
The work around is simply to manually add the GCD calcualted raster layers from the
Project/Simulations/Simulation Name/Output Rasters
Will be fixed in next release. Note that ArcGIS 9.3.X plugin does not seem to have this problem.