Hi,
I think both the issues could be solved by creating a .lyr file and add that to ArcGIS Explorer.
Part I:
- Add your raster/image service into ArcMap.
- Change Layer Properties > Symbology > Stretch type > NONE
- Right click the layer and save it a layer (.lyr) file
- Add this .lyr file into ArcGIS Explorer.
Part II:
- Add the multipatch to ArcGlobe
- Display it as floating layer and make sure it displays on Globe surface.
- Save the multipatch as a layer (.lyr) file.
- Add this .lyr file into ArcGIS Explorer.
++++
I have tested Part II and it seems to be working and I am pretty sure Part I should also work.
Let us know how it goes!!