looks as though you can only have one eeveelution on your team. i ended up on maps with a bunch of them, after i caught the first one i ran into i havent seen another since. so im assuming youll receive the one you have on your team for your bw game. i was hoping to get flareon but ended up with jolteon.
in other news, i have one of the best teams ever (so far), blaziken, ludicolo, cacturne, bibarel, jolteon and kingler :3
nix the only one idea, just caught a glaceon