I know Michael was working with them but I don't know if Juergen was. I don't think that either of them published anything on their experiences with them (assuming you're correct about Juergen) before they died. Ron Tremper worked with them in the mid 90s and wrote this blurb about them for me for the original CCIC (I just haven't finished updating all the species profiles and put it back up):
"Namib Chameleon (Chamaeleo namaquensis)
by Ron Tremper, Center for Reptile & Amphibian Propagation
Boerne, TX
In May 1995, the Namibian Wildlife Department gave us collecting and
export CITES permits for 5.10 Namaquas.
The area around Spitzkoppe had a dense population and from sunrise to
10:00 a.m. it was easy to find 15 chameleons per outing.
Only males were found in thorn bushes off the ground during the activity
period while females were always found on the ground and at temperatures
below 87F.
Males are colored tan and yellow and females are black and pink.
All 15 chameleons survived hand-transport back to our Texas facility and
were housed in three different conditions: 1) free-ranging outdoors
2) caged outdoors 3) caged indoors.
Six females laid clutches ranging in size from 10-18 eggs. The small
clutch size for such a robust lizard is due to the eggs size. Eggs
frequently measured 1.0 to 1.5" long.
Young hatched in 150 days and measured 2.5 to 3.0" in length. Sexes of
the hatchlings could be readily determined by color at birth.
Some 27 robust young from 6 different clutches hatched healthy.
Adult Namaquas are capable of eating 100-200 food items per day.
This is how they get their water needs in the terribly dry Namib.
Insect prey is merely crushed and the liquids extracted during
digestion. The large amounts of exoskeletons are passed through their
system quickly. This phenomena has been reported in the literature.
Sadly, and as I reported during my speech at the 1996 International Herp
Symposium, over the next six months all the adults and young died by
January of that same year.
The reasons for these losses is still only conjecture, but since the
Namaqua has evolved such a complex method of acquiring water I feel that
the Texas air humidity and/or the offering of external water sources
offered may have caused the failures.
The Namaqua is in good standing in its natural habitat even though many
are killed on the roads. It is not collected for the pet trade and
there are thousands of acres of prime habitat left in Namibia.
I want to thank the Namibian government for their assistance and
support."
Definitely not an easy species.
Chris