Since the couple of the last nightlies the time indicator (all kinds of modes) where not displayed in liveview and in hdmi mode on the 550D. The nightly from the 2013-09-20 displays the indicator only when audio is disabled from canon menu.
https://bitbucket.org/hudson/magic-lantern/issue/1710/time-indicator-lower-upper-infobars
https://bitbucket.org/hudson/magic-lantern/issue/1710/time-indicator-lower-upper-infobars