Hi Vlad 

I am using that kind of setup and I took the serctl script to start another instance of ser and I called it ser-vm .I created a voicemail configuration file and put it in /etc/ser/ folder. I specified a different pid file and put the correct path to the configuration in the ser-vm script ( the modified serctl script)

So when I want to start/stop ser I do serctl start/stop and when I want to start the voicemail instance of ser I do ser-vm start

Hope this will help!

J