Firefly Configuration for XPsp2
Install Firefly so that it starts on StartUp
Unblock access through the firewall as requested by the program
Enable UPnP Framework in the firewall exceptions
In the Options Menu
Voicemail - 3 ticks and 20 seconds
On the Firefly window, next to your number is a dot and a pulldown
Normally, use the pulldown to tick Away (yellow) or Unavailable (red) to stop incoming calls
When you are available, reset to Available (green)
Send a message anytime to another number
Some installations will not start at startup. If this happens, put a shortcut in the Startup folder in the Windows Start Menu
I see no reason NOT to have Firefly running all the time. There seems to be NO security problem.