Secondary payload to Asteroid

Has anyone at SSI looked into designing a secondary payload that
could be included in SpaceDev's (http://www.spacedev.com) Near Earth
Asteroid Prospector mission?
The design constraints seem to be pretty severe (2.4kg for the
detachable payloads, not sure about volume), but I was thinking
something along the lines of an inflatable solar concentrator
(parabolic reflector with a secondary mirror that concentrates the
sunlight behind/underneath the primary) and a GC/mass spec. It would
probably also require a robotic arm to scoop regolith into the
furnace, and probably a fair amount of mass to actually get the
payload to the surface in one piece.
I think they say they will support two or three fifty-minute
windows to relay communications back to Earth.

The two broad areas that could be looked at are metals refining and
volatile collection. Lot's of questions about both that I can't
answer:
What temperatures would be needed to purify a usefull metal? What
size solar concentrator would be needed to achieve that temp? Could
separation be done solely on the basis of temperature, or do we need
physical systems as well? Would an asteroid's gravity be enough to
help?
How deep into the regolith would you need to go to find any usefull
volatiles (water, various carbon based molecules)? I assume anything
'on the surface' would have been baked out.
The asteroid they are currently targetting is Nereus, but that may
change. There doesn't seem to be much known about Nereus as far as
its composition which would make it hard to decide exactly what to try
for.

Andrew