[Asterisk-Users] How to specify when to go to 102 priority

[yusuf]

Hi all,

I currently have this configuration.

exten => _X.,1,Dial(SIP/${EXTEN:1}@192.168.0.200:5060)
exten => _X.,102,Set(PRI_CAUSE=42)
exten => _X.,103,Hangup()


I have an Asterisk box connected via E1/PRI to Siemens PBX.  The siemens 
PBX sends my Asterisk box all cell phone call, and from the Asterisk box 
I dial SIP to a SIM gateway.  I am trying to implement a fail-over, as 
in where the sims are not working, etc, then I send a PRI_CAUSE back to 
the PBX.  However, this works in some cases, i.e. when I get a 'No 
circuit available' - 503 Service unavailable then it goes to the 102 
priority.  But it does not go to the 102 priority on ' 488 Not 
Acceptable Here' .

So my question is how to I make it go to priority 102 whenever it fails 
in priority 1

Any ideas??

thanks
yusuf