Don't know what you have in the way of supporting software, but this is what I do:
1. Use the film viewer to convert the selected clips to avi format (uncompressed).
2. Import those avis to a editing software (I use Adobe Acrobat) for editing, scequencing, and special effects (fade outs, ins). This will also give you a timeline for to build your sound track.
3. To edit/build the soundtrack, I use a program called Gold Wave. You can copy your AH sound files , and music mp3s to this and modify them to fit the appropiate duration and/or effect you need for your film.
4. Import your sound files to Adobe and place them in in your movie project.
Since the film viewer will not convert the sounds into a avi format, this is a very labor intensive way to make movies.
If your video card has a tv out, hook it up to a digital camcorder, and record the action live. Also have your AH film camera running (for the outside the plane shots). Capture these recording back into the pc as avis (with sound).
For your outside the plane shots, use the old AH film viewer (look for this on the clipboard when you open the AH game). This will give you full screen which is not available through the new viewer. Record the selected action on to the camcorder, and convert these back to the pc as avis.
Now follow steps 1 - 4 above to build your movie. I know this is a very high level look at the process, but it's a starting place for a very complicated process. If you have any specific questions, I'll try to answer them for you.