The site image can be placed on a layer, but not much else.
You can try this:
1. Switch to the layer menu
2. Create a layer for the site "Site_image"
3. Double click the site image to select it and in the layer menu, set it to "Site_image".
4. Turning the layer "Site_image" on and off, turns the site image display off.
I have not found a way to extract the site image imported from Bing, but you can create your own using Google Maps Pro and the "Save Image" function. I also like the open source windows application SasPlanet.
5. Create a new material with the new site image you'll create using Google Earth or SasPlanet.
6. Assign it to a grouped rectangle with the same proportions as the site image bitmap.
7. Scale the grouped rectangle to match the imported satellite image. You can temporarily set the material to semi-transparency.
8. You can then edit the site image bitmap in Photoshop or Gimp to include a transparency map of the areas you want "empty", save to a PNG and reassign that new version to the site image material.
9. Then set your visibilty parameters to mask the ground plane.
Voila, a hole in the ground (See GoogleEarth_Excavate.png). 🙂
Regards,
Luc