I'm trying to complete a living dex in Pokemon Black and to do so, I used an R4 cart to run Pokemon HeartGold and Platinum to get all the pokemon that are unobtainable in Black. I failed to realize before I started all this that to be able to transfer pokemon from gen 4 to gen 5, Pokemon Black has to communicate with actual gen 4 cartridges via DS download play.

It seems like the only way for this to be possible using an R4 cart is to somehow convert the cart into a copy of Plat/HG and have it function as so. How do I do this? Picrel is the cart that I'm using. I'm willing to buy a different or special type of flash cart if that's what's necessary to accomplish what I'm trying to do since it's better than buying legit copies of the games and playing them all the way through and catching all the 'mons all over again