Enum in a ClassDiagramm?

Hello,

Thanks for your Answer.
I try what you tell me, but in my program. There is no item(enumeration literal) in the kontextmenu) It looks like in this image.
I works with the professional edition and the version 6.0 (sp2_20070511).
What can be the reason, of that

http://www.imgwelt.de/uploads/E8E21GL5NMT.jpg