Parking Lot Status / Snom 360

I’m trying to get the Snom 360 phones (ver. 6.5.2) to blink when I have a call on Park. I’m using Asterisk 1.2.13 on Linux…
I’ve looked at a bunch of docs on the net, but I can still not make the LED’s blink.
I want to dedicate 3 function keys to ext. 71, 72 and 73 and I want them to blink when a call is parked at one of these extensions.
I’ve read that there is the metermaid patch which makes that function work… but isn’t that patch already present in Asterisk 1.2.13 ?

Please help…