I checked the editor and find it's working with images using the new document link.
I'm not sure, whether anything needs to be done, but maybe we could do the following thing:
in fileLinkCallbackBe() we overwrite the arguments for Document->getDisplayUrl(array(), '');, so the behaviour remains the same, only id is used.
and leave fileLinkCallback() unchanged, so the new link is rendered with the hash.
TODO: Check compatibility w/ richtext-editor, we should adapt it to use links w/o the hash.