Can anyone help me with something to convert my demos into something Windows Moviemaker can handle? I'm sure theres something allready here somewhere, but I used search and couldn't find anything. Thanks.

Start/Execute -> "cmd"

Go to Soldat folder and there type...

soldat.exe -demo demoname 0 100 0 1

After the demo is finished, all the BMP extracted files will be on the folder Soldat Dir/Demos/Extracted/

For more info read this:

Soldat\Demos\Extracted\ - This is were the extracted BMPs from Soldat SDM files are placed.
More information in the Soldat manual.

----------------------------------------------------------------
Demo files usage:
- Soldat.exe -demo name (freecam speed notexts extract)
(runs the game and plays the demo specified by name. Optional paramaters are:
freecam (0/1) - the user can freely change the camera (default 0)
speed (0-...%)- how quick the playback will be specified in percents (default 100%)
notexts (0/1) - no texts, menus or cursor will be displayed during playback (default 100%)
extract (0/1) - extracts the demo to BMP files (default 0). Later they can be used to make an AVI file in a program like "Bmp2Avi".
The sound can be extracted with a program like "Total Recorder". Please note that this can take time and is not recommended on slower systems. For better results specify lower speed (like 50%).
example:
Soldat.exe -demo demo12
Soldat.exe -demo demo19 1 200 1 0

Ripped from the file info.txt on folder /Soldat/Demos/Extracted/

Too bad the search engine doesn't work right now, because there are A LOT of topics about this.

You could start with this tutorial.
I found google.

The easiest way to play Soldat demos is using DDplayer by Pr0ger which you can download here.
Help yourself.

Thanks.