for french readers I found an interesting forum on the baobab only:
http://www.boutique-baobab.fr/forum
I got there aswell information about when to prune: before dormency break or in september. I've opted for the first choice and I'll chop the top in March 2008.
A moderator is advising for a fast growth or for recovery to give the baobab some egg shell because baobab are growing on the nature in a soil containing a lot of calc.
I put a hole egg shell in small pieces by the trunk of the baobab and going to see how it's going to react.