This method will allow you to unlock pro perks for online, but via Combat Training.
It's very helpful as you can easily boost desired perks in Combat Training with a friend.

Step 1: Unlock all challenges in Combat Training for the desired perk. This can easily be achieved by doing so with a friend.

Step 2: Get your friend to invite you to a Combat Training Lobby.

Step 3: Select "Create a Class" > *Custom Class > Perk, then press "X".

Step 4: Get your friend to change the lobby to Player Match.

Step 5: Select "Buy and Equip".

*The perk will be unlocked pro on the selected class in Combat Training.
*It will be usable, but not unlocked. Meaning to select the pro perk again you will need to do the glitch each time.

Plz Say Thanks and Rep


Edit: This Works For Xbox360 PC and PS3