I agree with the cutting/bending technique (that's what I did...a dremel works wonders in these situations). Otherwise, there really is no safe way to do it (you COULD try vice gripping the lines really tight to stop them from leaking, but, you would still have to get any air out of the lines later).
Cutting the brackets is not that bad. Invest in a dremel and it's not hard at all. Just be carful not to CUT the lines when cutting the bracket.