Record File based on Phone number instead of Unique Id

Dear Colleagues,
I have been successfully recording the outgoing calls. The recorded files are saved as ${outgoingchannelnumber}-${timestamp}-${uniqueid}.
I wanted it to be ${outgoingchannelnumber}-${timestamp}-${exten}.
When i change it in Macro-record-enable it records only in ${outgoingchannelnumber}-${timestamp}- .
How do i record the voice files under Phone Number.
I tried to use ChangeMonitor(basename) but to no avail.
Any help would be great help…
Warm Regards,

I’m using (* 1.2.4)