xpdl:WebService 

For WSDL 1.2 -- Invoke WebService, all IN Fprmal Parameters will be mapped to input message, all OUT Formal Parameters will be maped from output message

Element Information

Model

xpdl:WebServiceOperation , xpdl:WebServiceFaultCatch* , ANY element from ANY namespace OTHER than 'http://www.wfmc.org/2009/XPDL2.2'
Children: xpdl:WebServiceFaultCatch, xpdl:WebServiceOperation

Attributes

QName Type Fixed Default Use Inheritable Annotation
InputMsgName xsd:string required 
The name of inputMessage as defined in the WSDL which will help in uniquely identifying the operation to be invoked
OutputMsgName xsd:string optional 
The name of outputMessage as defined in the WSDL which will help in uniquely identifying the operation to be invoked
Wildcard: ANY attribute from ANY namespace OTHER than 'http://www.wfmc.org/2009/XPDL2.2'

Source 

<xsd:element name="WebService">
  <xsd:annotation>
    <xsd:documentation>For WSDL 1.2 -- Invoke WebService, all IN Fprmal Parameters will be mapped to input message, all OUT Formal Parameters will be maped from output message</xsd:documentation>
  </xsd:annotation>
  <xsd:complexType>
    <xsd:sequence>
      <xsd:element ref="xpdl:WebServiceOperation"/>
      <xsd:element ref="xpdl:WebServiceFaultCatch" minOccurs="0" maxOccurs="unbounded"/>
      <xsd:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
    <xsd:attribute name="InputMsgName" type="xsd:string" use="required">
      <xsd:annotation>
        <xsd:documentation>The name of inputMessage as defined in the WSDL which will help in uniquely identifying the operation to be invoked</xsd:documentation>
      </xsd:annotation>
    </xsd:attribute>
    <xsd:attribute name="OutputMsgName" type="xsd:string" use="optional">
      <xsd:annotation>
        <xsd:documentation>The name of outputMessage as defined in the WSDL which will help in uniquely identifying the operation to be invoked</xsd:documentation>
      </xsd:annotation>
    </xsd:attribute>
    <xsd:anyAttribute namespace="##other" processContents="lax"/>
  </xsd:complexType>
</xsd:element>

Sample