It will return its id and path, so fetch it with the id::
$CAU --mode user --send-csr user/client.csr.pem --get-crt <user-cert-id> user/client.key.pem
$CAU --mode user --get-crt <user-cert-id> user/client.key.pem
Voila, you have your key signed by caucase you started, and you became user of this caucase, so you now have the power to decide which service certificate requests will be granted and which will be rejected.
