Keep current swf visible, until a new swf has loaded into it's place?

programming flash
1

I’ve got a holder movie clip where I can load different swf’s into, by clicking buttons. I’m using the MovieClipLoader.

Because I’m going to use a loader layer (showing percent completed of download) with alpha to it, I don’t want the current swf to dissappear until a new swf has completed loading. If I could get this working the current swf would show through the alpha layer untill a new swf is loaded.

How can I achieve this?

This is a part of the code I’m using now:

button1.onRelease = function() {
    loader._visible = true;
    mcl.loadClip("swf1.swf",holder);
}

button2.onRelease = function() {
    loader._visible = true;
    mcl.loadClip("swf2.swf",holder);
}

When I use the code above, the current swf dissappears imediately when a button is clicked and a new swf begins to load.

I could use more than one holder, but then how would I know which one I’m currently using? … and there must be a better way to do it.

Thank you.