Creo que lo solucione agregando lo siguiente:
[macro-outbound-callerid]
include => macro-outbound-callerid-custom
exten => s,1,ExecIf($["${CALLINGPRES_SV}" != ""]?Set(CALLERPRES()=${CALLINGPRES_SV}))
exten => s,n,ExecIf($["${REALCALLERIDNUM:1:2}" = ""]?Set(REALCALLERIDNUM=${FROM_DID}))
exten => s,n(start),GotoIf($[ $["${REALCALLERIDNUM}" = ""] | $["${KEEPCID}" != "TRUE"] | $["${OUTKEEPCID${ARG1}}" = "on"] ]?normcid)
exten => s,n,Set(USEROUTCID=${FROM_DID})
exten => s,n,GotoIf($["foo${DB(AMPUSER/${REALCALLERIDNUM}/device)}" = "foo"]?bypass)
exten => s,n(normcid),Set(USEROUTCID=${DB(AMPUSER/${AMPUSER}/outboundcid)})
exten => s,n(bypass),Set(EMERGENCYCID=${DB(DEVICE/${REALCALLERIDNUM}/emergency_cid)})
exten => s,n,Set(TRUNKOUTCID=${OUTCID${ARG1}})
exten => s,n,GotoIf($["${EMERGENCYROUTE:1:2}" = "" | "${EMERGENCYCID:1:2}" = ""]?trunkcid)
exten => s,n,Set(CALLERID(all)=${EMERGENCYCID})
exten => s,n,Set(CDR(outbound_cnum)=${CALLERID(num)})
exten => s,n,Set(CDR(outbound_cnam)=${CALLERID(name)})
exten => s,n(exit),MacroExit()
exten => s,n(trunkcid),ExecIf($[${LEN(${TRUNKOUTCID})} != 0]?Set(CALLERID(all)=${TRUNKOUTCID}))
exten => s,n(usercid),ExecIf($[${LEN(${USEROUTCID})} != 0]?Set(CALLERID(all)=${USEROUTCID}))
exten => s,n,ExecIf($[${LEN(${TRUNKCIDOVERRIDE})} != 0 | ${LEN(${FORCEDOUTCID${ARG1}})} != 0]?Set(CALLERID(all)=${IF($[${LEN(${FORCEDOUTCID${ARG1}})}=0]?${TRUNKCIDOV$
exten => s,n(hidecid),ExecIf($["${CALLERID(name)}"="hidden"]?Set(CALLERPRES()=prohib_passed_screen))
exten => s,n,Set(CALLERID(name)=)
exten => s,n,Set(CDR(outbound_cnum)=${CALLERID(num)})
exten => s,n,Set(CDR(outbound_cnam)=${CALLERID(name)})
En el archivo extensions_override_issabel.conf, en realidad lo unico que modifique fue Set(REALCALLERIDNUM=${FROM_DID}) para que asi cuando uno desvie al celular salga con el DID de la extension.