Change Caller Id

Hi all,
Please help me about this situation as follows:

  • My B2BUA creates Invite message with From header is, then send to asterisk
  • My need is: when Asterisk creates other INVITE request to send to destination sip 2222, From header of INVITE request is other number such as, specially I must not modify current Asterisk server because Asterisk server belongs to my Customer and I have no permission to change code or reconfigure Asterisk.