Guided missile physic

Hello,

I have some question about physics of a missile or i would say behavior of a guided missile.

If i target an object that are in movement the missile must launch and rotate until it is aligned to that object all the time while thrusting forward.

My problems are...

1- How i detect that an object is aligned to another object or pointing in the direction of that object ?

2- Also.. how to detect which side the missiles must turn or rotate when i launch it ?

Thanks!

Found my answer here.. scirra.com/forum/homing-missile_topic50171.html i should have searched a bit more. Its nice that the software have this built-in!