Keeping 4:3 aspect ratio with Burn

I'm trying to burn a VOB file to DVD. It's 1280x480 and I have to convert it to MPG to burn it using Burn. The video is actually 4:3 and to make it stay that way, I run it through HandBrake first and make the output 640x480 (the file then becomes an m4v). However, when that gets converted to MPG through burn, it comes out s 720x480, pillarboxing the video within it.

Can someone give me advice or a better way to burn burn my VOB file to DVD? I've looked at some programs that first turn up in Google searches, but they only read 4 seconds of the video (which is an hour).