I specified the SOAPBinding in the EJB3 stateless session bean as follows:

Code:

...
import static javax.xml.ws.soap.SOAPBinding.SOAP12HTTP_BINDING;
...
@WebService(name="Kundenverwaltung",
targetNamespace="http://ws.hska.de/kundenverwaltung",
serviceName="KundenverwaltungService")
@BindingType(SOAP12HTTP_BINDING)

@Stateless
@Remote(KundenverwaltungService.class)
@RolesAllowed(ROLLE_MITARBEITER)

@WebContext(contextRoot="/hska/KundenverwaltungService",
urlPattern="/*",
authMethod="BASIC",
transportGuarantee="NONE")
@SecurityDomain("hska")
@EndpointConfig(configName="Standard WSSecurity Endpoint")
public class KundenverwaltungServiceBean implements KundenverwaltungService {...

The generated WSDL looks as follows:
Code:

...
<binding name='KundenverwaltungBinding' type='tns:Kundenverwaltung'>
<soap:binding style='document' transport='http://schemas.xmlsoap.org/soap/http'/>
<operation ...