Python Function SaveToLayerFile Not Working with Cached Basemap

Hi,
I am having an issue creating a layer file in python. I am trying to create a layer file of a cached Silverlight basemap using python in order to upload it to ArcGIS Explorer. However, the file type does not seem to agree with the –make layer tool and –save to layer file tool. I am confused because if I load the image in ArcMap and right click the layer, I am able to -save as a layer file. I have tried testing it out in a script in ArcMap as well as testing it in IDLE. Model Builder will not work either.

Thanks in advance,
Laura