I can connect to the external repository Vimeo.
When I import Vimeo as a CO, I can edit it: when I delete the text in that CO, the video is deleted too. In the source code of the CKeditor, I don't see any reference to the video.
I cannot insert a Vimeo in the CKeditor (in CO document type) via the button Content Object. The only media files that can be inserted are: Soundcloud, Qwiki and Youtube.