Settaggio freccie di scorrimento per filmato

[banalik]

Ho realizzato una barra di scorrimento per un clip filmato.
Per chi volesse vederlo

http://www.banalik.mrw.it/
'skip intro' per le due intro
e poi dal menu scegliere 'Portfolio'.

Con lo scroller non ci sono problemi.
Se invece faccio scorrere con le frecce
la scorrimento arriva fino ad un certo punto
e poi si ferma.
Dal codice non riesco a trovare quale sia il valore da cambiare.
Qualcuno può aiutarmi?

Questo è il codice AS all'interno dell'istanza dello scroll:

this.startScroll = function(active, type) { // declare the startScroll() method
if (active) { // if the up, down, or middle scroller are pressed
this.type = type; // set the type variable on the scrollBar instance
if (type != "mid") { // if the middle scroller is NOT pressed
this.onEnterFrame = function() { // define an onEnterFrame() method
if (type == "up") { // if the up (left) button is clicked
if(target._x <= target.startX-increment){ // then check to see if the current X position of target is less than its starting point (minus the increment that's going to be added)
target._x += increment; // if it is less, then add the increment to the X position of target
} else { // otherwise
target._x = target.startX; // set the X position of target back to its starting point
}
} else if (type == "down") { // otherwise,if the down (right) button is clicked
if(target._x >= target.endX+increment){ // then check to see if the current X position of target is greater than its ending point (plus the increment that's going to be added)
target._x -= increment; // if it is greater, then subtract the increment from the X position of target
} else { // otherwise
target._x = target.endX; // set the X position of target to its ending position
}
}
updateScroller("arrow"); // update the position of the middle scroller
};
} else { // otherwise, if the middle scroller is pressed
this.onMouseMove = function() { // establish an onMouseMove() method
updateScroller("mid"); // update the position of the middle scroller and content
updateAfterEvent(); // refresh the stage
};
}
} else { // if the up, down, or middle buttons are released
this.onEnterFrame = null; // remove the onEnterFrame() method
this.onMouseMove = null; // remove the onMouseMove() method
}
};
function updateScroller(type) { // define the updateScroller() function
var a = scroller._y; // distance traveled by scroller
var b = 59; // total length of scrolling area
var c = target.rangeX; // total span of target clip
var d = target.startX; // offset position of target clip
var e = target._x; // current position of the target clip
if (type == "mid") { // if the middle scroller is engaged
target._x = (c*(a/b))+d; // then set the X position of target to the result of our equation
} else { // otherwise, if the arrow buttons are engaged
scroller._y = b*((e-d)/c); // then set the Y position of the middle scroller to this result
}
}

// this .as file establishes movieWidth and movieHeight (in pixels)
#include "getMovieSize.as"

increment = 10; // this value (in pixels) will be added or subtracted with each click of the up or down arrows, respectively
target = _parent.content; // target MovieClip object
target.startX = (target._width/3.0); // starting position (offset) of target clip
target.endX = movieWidth-(target._width/2.2); // ending position of target clip
target.rangeX = target.endX - target.startX; // total span of target clip
target._x = target.startX; // set the target clip to its starting position