Specify alternate configuration file/registry path on Windows?

[Randolf]

I'm trying to find a way to run multiple Mumble instances on Windows each with it's own configuration. I'm playing with the -c command line option trying to run with either a config file or registry path, but can't seem to get it to work, whatever I give it, Mumble just won't start, without any error message either on stdout or message box.
Is there any way to tell Windows Mumble to use a different configuration than the default registry path?

Edited April 30 by Randolf

[Krzmbrzl]

You also have to pass the -m option to allow multiple instances in the first place. Otherwise, the executable will think that you want to send RPC commands to the already running instance