Creating a Mesh asset inside the editor

I am trying to save a generated Mesh from an imported .obj file. I basically take a sphere which I have created and UV mapped in blender and then modify it. This works fine, I get exactly the result I want, now I want to save out this new mesh as an Asset, which is where I have trouble.

When I try to save the Mesh using AssetDatabase.CreateAsset, i can see an object in the Project panel but it has no type, inside explorer I can see that it’s a 64kb file. Do I need to add a file extension?

When I look at the Meshes I have imported they seem to be multiple objects is this necessary or is it possible to save a single Mesh asset by itself?

I have tried using the objexporter script from the Unify wiki but the UVs get ruined in the process.

Any help would be greatly appreciated.

.asset

It says so right here.:

You must ensure that the path uses a
supported extension (‘.mat’ for
materials, ‘.cubemap’ for cubemaps,
‘.GUISkin’ for skins, ‘.anim’ for
animations and ‘.asset’ for
arbitrary other assets.)