+1 in caller id

Hello,

How would I strip a +1 off an incoming caller id for one sip trunk?

I’ve tried the following:

Added to extensions_custom.conf

[from-sip-custom]
exten => s,1,SetCIDNum(${CALLERIDNUM:2}) ; get rid of the +1 in calling number zingotel sends
exten => s,2,Answer
exten => s,3,Goto(from-sip-external,s,1) ; in extensions.conf

and set the incoming context for the trunk to from-sip-custom but it doesn’t seem to calling up the above code.

Any pointers on what I’m doing wrong?

Thanks,

Tom