[gmf-dev] activate print preview dialog

[Ralf Heydenreich <rheydenr@xxxxxxxxxxx>]

Hi all,
I've modeled a  GMF application which runs fine. No I want to add a 
print preview dialog. I see that in the generated classes 
(..processmodel.model.diagram.providers) is a class 
(ProjectnameContributionItemProvider) that holds a createAction method 
which in turn calls RenderedPrintPreviewAction. But I don't know where I 
have to activate this class. In the extension points I'm not able to add 
this class for an item because it's not in the list.

How can I do this? Thanks in advance,
Ralf.