Downloading Rock Band 2&3 Songs? to PS4

I heard that you can now download all your rock band 3 DLC songs (Also Rock band 2 im guessing but not 100% sure)

I've logged into my PS4, searched 'Rock Band 4' but nothing shows..

ANyone have any news or info in regards to this? I've got it pre ordered and wiill own Rock Band 4 VERY SOON

I'd really love to get started on downloading some songs before hand if its possible.. Anyone??

Most of the DLC works, with some that is still broken right now.  The Rock Band 1 and 2 exports are still being worked on too, just not available yet.