Technically i think it 'may' be possible. practically i don't think so.
When i changed mine I remember needing to remove the front cover (and crank pulley) which could not be done with engine in the car. In theory if you are able to get the tensioners disengaged, you should be able to do it with engine in.
Either way you'll be getting intimate with your car.
let us know how you make out
p.