there is some stuff called 'Corrosion Block' which I've been using and it seems to hold up pretty well. Among other things, it works great inside steel frames to keep them from rusting from the inside out.
I'd avoid putting grease on them bearings because grease will attract dirt and you don't want to attract dirt to your bearings. White Lightning or any wax based lube should do the trick, but I usually drop a little Triflow on mine from time to time. What is now rust, will turn into a protective layer if you oil it up from time to time, keeping new rust from forming. Like gun bluing.
I could be wrong, but I think that those bearings are very high in carbon, which makes them really hard and gives them a really long life. The downside of high carbon steel has always been corrosion, but if the seals on these bearings are still doing their job keeping the grease in and the water out then no worries, mate!