[Evolution] cannot assign tasks

[Kai Andresen <kaiandresen web de>]

Hi,
having installed evolution with the ximian connector everything seems to work 
fin, except for assigning tasks to other persons.
This option seems to be built-in, but is for me greyed out.

Does this option usually work with exchange? I have not found anything, 
suggesting it does not...
If not: are there workarounds?

Thanks
Kai