I still have this storm in my brain, so I keep on brainstorming:
How about this approach (it would suffice the requirement that the editing is done in Word):
The text to translate (1 sentence ... 5 sentences) is copied to a second pane in Word, either above or under the main document. The whole content of this document is sent to CafeTran for preparation and the result is pasted/set back to this auxiliary document. You make the further modifications and once you're happy, you send it to the main document, where it's inserted at the appropriate position.