Tweening via Code Help (please)

OK, so I’m going places but I’m having a hard time with this tween, I’m attempting to have, “firework” once added to the screen, move from its current position, to the position of the mouse
OK, better
the “firework” is moving at an odd pattern, based on the code I have written, I have gathered it is moving like this.
Example – _xmouse = 20
the firework, is moving 20 pixels, relative to 0 being the current X value of it.
so instead of it moving along the x axis relative to the stage to the x value of the mouse, its moving it relative to itself the amount of pixels the mouse is relative to the x value of its location to the stage
function tweenfirework(){
var xPosT:Tween = new Tween(firework, “_x”, None.easeOut, firework._x, _xmouse, 1, true);

//var yPosT:Tween = new Tween(firework, "_y", None.easeOut, firework._y, _ymouse, 1, true);