Try
Try connecting to altwfc, all you have to do is use the IP address listed there, you don't need to patch anything.
https://github.com/barronwaffles/dwc_network_server_emulator/wiki
Then set your console's date to the tournament you want to download, and it should work. Let me know if it works, as I haven't played BW2 yet, so I'm curious.
If it doesn't work, apparently there is this:
https://projectpokemon.org/home/for...ad-tournaments/?do=findComment&comment=230489
However I'd advise to first try if altwfc works, since it's faster and you don't need to mod anything.
Btw there's also this (different IP though), in case you'd like to try online trading.
https://pkmnclassic.net/