How can I update background color?

I tried:

SWF := TSWFStreamReader.Create(AStream);
if SWF.TagInfo[I].TagID = tagSetBackgroundColor then
with TSWFSetBackgroundColor(SWF.TagInfo[I].SWFObject).Color do
// and here set new RGB

but color is not changed.

How to do it?

BTW: I'm using v2.3 and I don't want to update to v3.