The purpose of the functional requirement is to specify a login name to identify which integration is used in order to create the Service Request (within Siebel).
WSDL permit Service Request creation if an Administration name/password is specified. Anyway, consume the wsdl with SOAPUI request using whichever login of interest is available.
So, change the web service url in the SOAPUI request (username/password of the interested login in the url), for instance, using USERA the url request is such as:
http://localhost/eai_esn/start.swe?SWEExtSource=WebService&SWEExtCmd=Execute&Username=USERA&Password=USERA