[PyMOL] Cutaway surface

Hi all,

Is there any way good way in pymol of displaying a slice through a
surface and block colouring the 'inner' face of the surface.=20
Basically, I would like to generate a figure that looks like part (b)
of http://www.nature.com/nature/journal/v432/n7014/fig_tab/nature02988_F3.h=
tml
using pymol.  I have tried playing with the lighting models and
backpace culling (a-la set ambient=3D0; set direct=3D0.7; set reflect=3D0.0=
;
set backface_cull=3D0) but they are not quite what I am after.

Can anyone recommend a good way to achieve this effect?

Thanks,

Stephen

--
Stephen Graham
Crystallography Group
School of Molecular and Microbial Biosciences
University of Sydney