I'want to take some swearing our of some movies that I have on DVD. So far I'm doing this by bringing up the Sound line editor and adding some marker points and dragging the volume down.   This works well except when I go to export the AC3 option is gone and I'm only left with 2 channels.   I understand why this is due to Dolby licensing.  Is there a way that you can cut the sound for a few seconds but maintain the vision so that the AC3 is maintained?"

Yes, this limitation is due to the lack of an AC-3 encoder.  However, without the capability of direct sound modification,  the editor is able to add silent audio segments for AC-3 data.  Hence, the only way is to manually find the audio blip and taking out the part by deleting the corresponding segment on an audio track, using the following trick:  duplicate a video clip in the audio track  by dragging and dropping the video clip while holding down the Control key; and then mute the video clip.  Please also note that one drawback of this "work around" is that the result sound may be discontinuous.

Please note the above note does not apply to MPEG Video Wizard DVD, which has added full AC-3 encoder support.