ActionScript 3.0 :: Load Movie - File Resized Or Rescaled Automatically

I have a an swf (A) that loads external swf files (B). I use the loader or UILoader classes for this. I do not have the source of the loaded flash files, I have source only for files A. The loading works fine. The problem is some of the loaded files resize or rescale themselves. Doing some research I realized that they use the Stage.width/height for calculating their size/scale. This approach works fine, when they are embed to a website, because they get a stage sized for their needs. But when these files are loaded in my MovieClip, they get the stage of the loader swf(A), and that is definitely have different sizes.

Approach 1: In this approach I tried to create a fake stage for the loaded movies with the right size for them. This failed at several points: Stage is a singleton, and the stage property of the objects are Read-Only. On top of that Stage is a built-in class, without AS source. My first question is that is there any possibilities to override this class, or use this approach?

Approach 2: I planned to design a web-service (not in actionscript), that predownloads the swf, decompile it, replaces the references to Stage.width/height to the correct values, compile it again, and passes the generated swf to my Loader. On decompilation/recompilation, it should be as fast as possible, and I'd like to modify the swf as little as possible, so I prefer to not decompile the swf completly, just as much as needed.

After some googling I found swix kit, or simply swix. It generates not the source but an xml file equivalent to the swf. The problem is this xml format is not documented, or at least I haven't found it. I found references for Stage, but I have no idea how to modify that file.

Code:
<ConstantPool>
<Constant Name="Stage" />
<Constant Name="width" />
<Constant Name="height" />
<ConstantPool>

How to replace the Stage.width/height values with a simple Number in the xml? Does this tool have a command-line interface?