Well I don't know if this will help but I'll tell you guys anyway.
1)Make sure you have saved films.
2)Go on the Reach Beta and leave it.
3)Turn off your Internet connetion.
4)Back at the Beta go back to the Main Menu (don't exit the Beta as you will have to start again).
5)Go into Theater or Customize your Spartan and Emblem.
There you should still be in the Beta after the cut time.
Remember to turn your internet connetion back on but don't sign in live.
I thought I might tell you guys this so you can still watch your Theater and take shots.