Two years ago we added logic to parse the isup-oli parameters, that arrive as part of the FROM Sip header. We need to finish the job and allow setting of this parameter for outbound calling, both in traditional SIP channel and PJSIP, which I believe will replace all instances of the old SIP channel soon.
Right now, if we try to set CALLERID(ani2)=$
, there is a runtime error because this variable is read-only. The business community around Asterisk needs this feature and there is no known workaround.
I am also writing about this to the developer list. If somebody wants to propose a patch, I can contribute to the bounty.