Welcome to the forums, and sorry for the trouble this is causing! If you haven't already, you'll want to email the
support ninjas about this; we all browse the forums as we're able on top of our other duties, but in this case, the first Omni-ite to see your post has insufficient OmniGraffle-Fu to answer your question.
If you email the support ninjas, though, you're guaranteed an answer from someone more knowledgable in that app than I. :-)