asterisk users - Apr 2004 - Proble with sample.calla and setvar

Hi

I'm using the following sample.call

Channel: Zap/2
MaxRetries: 2
RetryTime: 60
WaitTime: 30
Context: fromfax
Extension: 3
Priority: 1
SetVar: num=777777

in extensions.conf I have:

[fromfax]

exten => 3,1,Wait,1
exten => 3,2,SayDigits(${num})
exten => 3,3,Hangup

But it only says 10 it seems variable is not set

do I use correctly SetVar ? 
How can I  read variables assigned using SetVar ?

Thank you

Bye
    Lorenzo