Help creating non gen V legendary Pokemon for b/w

Hello. I'm posting in regards to how to create a legal legendary Pokemon for black/white that is from other gens.

For instance, say I want to create mewtwo. I downloaded the legit file from Pokemon database. It passes the legality checker. I then go in and edit the IVs, EVs etc, give it a proper PID, give it proper moves. I don't change the id/Sid, because unless I'm wrong, this Pokemon MUST appear as traded, because it's impossible to catch one in black/white. I do change the original trainer name however, and set the pokemons name to original; mewtwo.

Ok, so now I've got my perfect legal lvl 100 mewtwo. I check the legality checker, it passes again. Now here's the issues;

I load the Pokemon into my game. I can't seem to enter any wifi related features with mewtwo, when I enter GTS for instance it simply says no access point in range? But I'm clearly connected to wifi. I try to enter a random single battle over wifi, and it says no Pokemon with duplicate items, no eggs etc. what's wrong?

Also, mewtwo says "apparently met at lvl" instead of "apparently arrived at" am I supposed to change the met at information?

Thanks a lot, because there are a lot of non gen v legendaries I'm planning to make. I want them to be legal mostly for the purpose of being able to freely trade to newer games, do that when black/white 2 come out, I don't have to fudge around with pokesav again, I can just trade these Pokemon right on over. Etc.

Also I'm at work, when I get home I can try to upload the relevant pkm file if need be.

Mewtwo is one of several banned Pokemon when it comes to the Random Match feature in BW.

http://projectpokemon.org/forums/announcement.php?f=83

Also, read forum announcements.