[PyMOL] color individual residues on a surface?

[Michael Bovee]

Hi PyMOL'ers

I'm trying to figure out how to do something that looks like the 
following figure:
http://www.uvm.edu/~mbovee/structures/surface.png
It seems any individual residues I color always map onto the cartoon 
ribbon representation rather than onto the surface representation.  Is 
this currently possible in PyMOL to do what is pictured in the link 
above?

Thanks,
--Michael Bovee, Ph.D.
Dept. of Biochemistry
University of Vermont