RM to AVI: SUPER changes AR from 4:3 to 2:3......

[Ruut]

I have a couple of RM files, which I would like to convert to AVI XviD. SUPER 2007b21 converts both the audio and the video, but the resulting Aspect ratio changes to 2:3: original is 640x480, AVI is 320x480. SUPER uses the Mencoder, framerate is 29.97 and bitrate almost 400 k, AR set to 4:3.
Is there anything I can do in the settings of SUPER to avoid this?
Or is there a way to 'stretch' the video without re-encoding?
Or is there another RM to AVI converter, which does a better job than SUPER?

[Krispy Kritter]

Try opening the files with a tool such as mpeg4 modifier and see how the files are set. You may be able to just change the AP to 4:3.