When using the command fts-config-set a warning message appears by recommending the use of REST interface. But, REST interface does not provide an alternative for the fts-config-set command, it has to be done with curl.
warning : fts client is connecting using the gSOAP interface. Consider changing
your configured fts endpoint port to select the REST interface.
SOAP 1.1 fault: SOAP-ENV:Client[no subcode]
"CGSI-gSOAP running on fts703.cern.ch reports "