Still interested to know what the preferred method of acheiving ths is, or if it is in fact already implemented, but in the mean time, here's a workaround to simulate an incoming call uing 7777 same as other distros.
Create a new custom app and call it something like "simulatecall".
Just add the following line:
exten => 7777,1,Goto(mainmenu,yourphonenumber,1);
Where yourphonenumber is taken from the top of the [mainmenu] section of extensions.conf
This should now be in extensions.conf
[simulatecall]
; Simulate an incoming call from an internal phone
exten => 7777,1,Goto(mainmenu,yourphonenumber,1);
That's it.
Mark
Really liking SAIL btw.