Need to disable/Grayed out Unreseve button for Order lines

Question

Hi All,
In Back to Back order process once the order is progressed, the requisition will be created and Quantity will be reserved for PO to be received.
Some of our users want go and Unreserve this by the below methods.
1) Tools --> Scheduling --> Unreserve
2) Right Click on the order line --> Scheduling --> Unreserve
We need to Disable or Grayed out this Unreseve option for ATO Flagged lines.
Can anyone let me know if this is possible.

Answer 1

Ok , Ned , well your Guidance really worked , thanks alot for that.
I made it work , though since i am very new to AS3 , i really had to experiment , here is the final Code :
import flash.events.MouseEvent;
stop();
var note1:Mc_Notice1 = new Mc_Notice1;
var note2:Mc_Notice2 = new Mc_Notice2;
var notes:Array = [note1,note2];
//var count:Array = new Array(1);
var count:int;
count = 0;
btnload1.addEventListener(MouseEvent.CLICK , load1);
btnload2.addEventListener(MouseEvent.CLICK , load2);
function load1(Event:MouseEvent):void
  addChild(notes[0]);
  notes[0].x = 100;
  notes[0].y = 100;
  count ++;
  trace("Counter Value:" + count);
  if ( count == 2)
  btnnxt.addEventListener(MouseEvent.CLICK , nextframe);
function load2(Event:MouseEvent):void
  addChild(notes[1]);
  notes[1].x = 100;
  notes[1].y = 100;
  count ++;
  if ( count == 2)
  btnnxt.addEventListener(MouseEvent.CLICK , nextframe);
  trace("Counter Value:" + count);
function nextframe(Event:MouseEvent):void{
  trace("Mouse Enabled");
  nextFrame();
Once again , Thanks alot for the help and Guidance
Best Regards