How much at once? Less than a page? Full page? Multiple pages?
How are these editors presenting this prettified source to the user? If HTML, and you can access the raw HTML, various workflow possibilities arise.
Does the editor have the ability to export or save the prettified to RTF, Word, PDF, HTML, etc?
Does the editor have at least have the ability to print the prettified code? Print to PDF and import, then.
Yup, that makes sense – I've included views from my preferred XML/DITA environment with the "print to .pdf" option, and very smart they look too :-}