I don't know if you still care about this, but have you tried the edit-replica option in rmcli. I do something like this

if-not connect host=myhost port=65432 then exit 1

if-not login user=myuser password=mypass then exit 2

if-not run-job name=mycopyjob appset=myappset(Administrator) then exit 3

if-not edit-replica position=last appset=myappset(Administrator) display-name=myuniquename then exit 4

exit 0

Hope this helps.  BTW I am using 5.4.1 in case that matters