You can assign your own keyboard shortcuts to VSdocman commands. You can do it the same way as for other Visual Studio commands:

1.Go to Visual Studio Tools - Options...

2.Select Environment | Keyboard page.

3.Assign shortcuts to the following commands (enter "vsd" to Show commands containing field to filter out other commands):

VSdocman.CommentEditor

VSdocman.AddComment

VSdocman.OpenVsdocman