Extracting bitmap from SWF

Hi,
my question could sound noobish, but… I’m having a headache trying to do a very simple operation.

I have loaded a SWF with Greensock’s SWFLoader, and now I want to instance a Bitmap with linkage “DotMatrixPattern” and use its Bitmap content to create a pattern with beginBitmapFill: the problem is… how do I extract the Bitmap from DotMatrixPattern?

I am able to instance DotMatrixPattern, but then? DotMatrixPattern.rawContent? No! undefined!

What am I doing wrong?