I haven't done network sniffing, or flash decompiling to see if this SWF file is just a wrapper around a FLV file or something. If that's the case, you may be able to switch to a different player, and handle it, but otherwise, there may not be a way (but then again, I'm not a Flash expert).
This is not an "answer" but, just to share what I think: I believe this (resizing) depends on the underlying flash (swf) file being able to handle scaling or not. In this particular case, it seems that "Logging-into-cPanel.swf" does not handle it, and does not pay attention to the size of the canvas it resides, and always centers itself (i.e. cropping when the container is smaller)