[Asterisk-Users] Spoofing CallerID on Demain

[Andrew]

I have an outgoing line that allows me to set my caller id.  I want to be
able to change the caller id when ever I place a call using this line.  I
would like my user to press 7, then be prompted for their 10 digit caller id
number, then be prompted for the number they would like to call in the form
1NXXNXXXXXX.

How can I accomplish this???

Right now I am using this script that users have to dial
_71NXXNXXXXXXXXXXXXXXXX , where the first 12 digits are the number to be
called and the last 10 are the caller id.

My dialplan:

exten => _71NXXNXXXXXXXXXXXXXXXX,1,SetCallerID(${EXTEN:12})
exten => _71NXXNXXXXXXXXXXXXXXXX,2,StripLSD(10)
exten => _71NXXNXXXXXX,3,Dial(~~~,${EXTEN:1})

exten => h,1,Hangup
exten => i,1,Hangup
exten => t,1,Hangup