On the data source level <Datasource> of the KiWIS config.xml the connection information and the service have to be added:

<WAPIConnection>
  Enables a WISKI API connection. The API must be active in the WISKI Server and reachable via its network port. Installation and configuration will usually be done by KISTERS.
<apiURL>http://localhost:<REST API Port>/</apiURL> (1)
  The target URL.
<apiVersion>0</apiVersion> (1)
  Only version 0 supported at the moment.
<user>ModelWrite</user> (1)
  The WISKI user should be equal to the WDPConnection user
<password>###</password> (1)

The WISKI password (encrypted) should be equal to the WDPConnection password.
  <domain>WISKI</domain> (1)

The WISKI domain should be equal to the WDPConnection domain. </WAPIConnection>

<KiWS/>
   Enables the KISTERS WriteServices, currently without further options.