The tag team championship belts ARE in the new code (as are the other title belts).
To start the Tag Team Championship match, you must first claim the "Money In The Bank" briefcase by hitting the top light on the "Skill Shot" (either by one short-plunge "Skill Shot" or three separate full-plunge attempts on each ball when the top light is lit). Once you have claimed the "Money In The Bank" briefcase & are not in a match, you hit each green "Tag" standup, then shoot the green "Tag" insert at the left scoop. The DMD will then instruct you to shoot either ramp to start the Tag Team Championship title match.
The "read me" file states:
- Added new rule to Money in the Bank. Rule now starts championship to
the next non-active wrestling match or Tag Team Multiball match.
***EDIT: After playing some more, it looks like you DO NOT need to win the U.S. Championship Title match first in order to start the Tag Team Championship match. As long as you've first claimed the "Money In The Bank" briefcase by hitting its skill shot (either by one short-plunge "Skill Shot" or three separate full-plunge attempts on each ball when the top light is lit), you can proceed to start Tag Team Championship after you've won your first match.