still nop possible. the main problem on nintendo server. is have some filter to avoid that. also is not just add on data entrie, is will need change save structure algorithm since pokemon BW and old one is using different method and encrypt i think (well maybe wrong). for now is hard. and is not fair for gamefreak. just using pokemon BW for you main ROM for you mod. don't trying renew old game, is need 1-3 year to do that (if you alone).Well, it'd be possible to add the gen V monsters back to the game, however the transfer functionality and consistency between the memory location of the Gen V monsters in B/W and the memory location of the added gen V monsters in HG/SS D/P/Pt would be the main issues, I think.