On what grounds will it "not be a problem"? I don't think you can make that statement whatsoever. It's hard enough redeeming miles for one segment using Flying Blue, nevermind multiple segments. I have every sympathy for the OP. Unfortunately I would just give up now and aim to use the miles in a less "ambitious" way. The thought of trying to book this itinery, by post or even by phone, makes me want to go and lie down with a tea towel over the lamp shade.