Mono audio in Vision

I have 2 videos I’m combining into a single DVD movie. One video has normal stereo sound. The other has only one channel producing sound. Both are segments of the same subject and really need to have the audio the same to sound right. Is there a way to force both videos to mono audio before transcoding and burning to disk?

Found a work around. Neither NERO Vision or ShowBiz2 had a means of forcing pseudo stereo or mono on both channels. But, cheapie little OEM MyDVD did. Go figure. I had to load into MyDVD, set to use right channel, then transcode to DVD and import into NERO Vision to complete my movie. Surely there’s a better way to handle it???