That's not exactly what I said, but it seems to work for you. Although, someone once said doing this with just one controller does something funny with your profile (I don't know). I do know I've tried doing this once with just the one controller and it didn't work; as soon as I switched back to my dynasty team, my opponent's uniform reverted to default.
My method was to use two controllers:
- Move P1 to your dynasty team (should happen automatically).
- Move P2 to your opponent's team.
- Select P1's uniform, making sure it shows your profile (if that is important to you. Once you're done here, press whatever button you normally do to advance to the game; the box under your dynasty team should say "Ready."
- Select P2's uniform; the profile here should read User 2 (or something like that). Once you've done that, press whatever button you normally do to advance to the game.
- You'll have to do the coin toss for both teams (here's the drawback as you can "cheat" your way to an advantage for your dynasty team).
- Before the kickoff, pause the game with P2, make your way to "Select Sides" and put P2's controller to the center. The change will take effect after the kickoff (another drawback, as you have a chance to "cheat" again).
Voila, you have selected both teams' uniforms.