Trap Focus repeated automatic use.

[SD]

I am using the trap focus on a 50D with the 2.2 release of ML but would like to use it repeatedly.  I am new to ML so may have missed this somewhere.

Specifically I would like to put the camera on a tripod,  keep the camera on focus half press, and just let pictures be taken as things come into focus.  Right now it only takes one picture as I keep it on focus half press. You have to release and half press again to get another picture.

Thanks,
     SD

EDIT: The Trap Focus menu item for me only has "Off" and "Hold", there is no "Cont."  Is this an interaction between 2.2 and a 50D?

EDIR 2: The 2.3 release has the CONT mode in there on my 50D, hence I am good to go.