transitionManager

I am using Transition Manager to fade in several MovieClips of maps.

import mx.transitions.*;
import mx.transitions.easing.*;

trans2 = TransitionManager.start(map2ndMC, {type:Fade, direction:Transition.IN, duration:2, easing:None.easeNone});

Is there extra code to kill the instance of the transition? or find out when the transition is complete? I'm finding that on occasions the transition doesn't initiate. I thought that the enterframe code embedded in the transitionManager might be interfering with my main movie. Does anyone know if you are suppose to end the instance once it has completed?

The code above seems to work alone (sometimes).