Replacing all instances of the old movieclip with instances of the new movieclip, could be an easier solution. All instances of the old movieclip can be found by parsing the timelines of the flash document. Here is some code:
var _doc = (fl.getDocumentDOM() ? fl.getDocumentDOM() : fl.createDocument());
var _lib = _doc.library;
fl.outputPanel.clear();
ReplaceItemWithItem('Game Layouts/card holder', 'Game Layouts/card holder new');
function ReplaceItemWithItem(oldmcname, newmcname)
{
var item1 = GetItem(oldmcname);
var item2 = GetItem(newmcname);
if (!item1) return false;
if (!item2) return false;
if (oldmcname == newmcname)
return true;
return ReplaceAllItems(item1, item2);
}
function ReplaceAllItems(item1, item2)
{
var timelines = _doc.timelines;
var i, l = timelines.length;
var items = _lib.items;
var changed = false;
// Main timelines
for (i = 0; i < l; i++)
{
var timeline = timelines[i];
changed |= ReplaceItems(timeline, item1, item2);
}
// Timelines in library items
for (i = 0, l = items.length; i < l; i++)
{
var item = items[i];
switch (item.itemType)
{
case "movie clip":
case "graphic":
case "button":
changed |= ReplaceItems(item.timeline, item1, item2);
break;
}
}
return changed;
}
function ReplaceItems(timeline, item1, item2)
{
var changed = false;
if (timeline && item1 && item2)
{
var layers = timeline.layers;
var lay, layl = layers.length;
for (lay = 0; lay < layl; lay++)
{
var layer = layers[lay];
var frames = layer.frames;
var fr, frl = frames.length;
for (fr = 0; fr < frl; fr++)
{
var frame = frames[fr];
if (frame && frame.startFrame == fr)
{
var elements = frame.elements;
var e, el = elements.length;
for (e = 0; e < el; e++)
{
var elem = elements[e];
if (elem && elem.elementType == "instance") // Elements can be empty
{
var item = elem.libraryItem;
if (item.name == item1.name)
{
elem.libraryItem = item2;
changed = true;
}
}
}
}
}
}
}
return changed;
}
function GetItem(itemname)
{
if (!_lib.selectItem(itemname))
{
alert("'" + name + "' does not exist in the library!");
return null;
}
return _lib.getSelectedItems()[0];
}
Hope this helps!