This is done from the command line:
Code:
md c:\my_presets
md c:\my_presets\.ffmpeg
copy <existing presets directory> c:\my_presets\.ffmpeg
setx HOME c:\my_presets
Use
Code:
setx HOME c:\my_presets /m
to make it system wide, not only for the currently logged on user. Close the command prompt, open a new one and try to encode with a preset.
I also found that this environment variable method eliminates the need for a "\usr..." directory on each drive I want to run my scripts from.