That description does not seem to match the plant at my pic. I also checked a German source: http://de.hortipedia.com/wiki/...
but they do not describe the berries. It seems to me that the name given in the Botanical Garden of Berlin was wrong. Unfortunately I do not have any more pictures of this plant, i do not remember
if I took more (i usually do) or that i threw them away (when they are no good). For the moment this identification should be treated with a lot of doubt. When I will visit Berlin I will take a fresh look at the whole plant. Unfortunately I do not visit Berlin that often.
Thanks for your remarks!!