AutoCAD .NET :: Obtaining Texture UV Coordinates?

I am trying to write a 3d geometry exporter for AutoCAD.

Firstly, is iterating through the document database, and processing any Solid3d, Region & Body entities the best way to do this, or is there a faster way to access the 3d geometry?

Secondly, I assume using the first approach above, I need to process each entity as a Brep in order to get the vertices, polygons, etc.  In this case, how are the UV coordinates for each vertex obtained?