title: add service reference not generating specified field for optional value type
body: <p>I have the following in an xsd -</p>
  
  <pre><code> &lt;xsd:complexType name="isPermissableRq_Type"&gt;
      &lt;xsd:sequence&gt;
        &lt;xsd:element name="accNr" type="ObjectId_Type" minOccurs="0" maxOccurs="1"/&gt;
        &lt;xsd:element name="bankNr" type="BankNr_Type" minOccurs="0" maxOccurs="1"/&gt;
      &lt;/xsd:sequence&gt;
    &lt;/xsd:complexType&gt;
  
  &lt;xsd:simpleType name="BankNr_Type"&gt;
      &lt;xsd:restriction base="xsd:long"&gt;
        &lt;xsd:totalDigits value="10"/&gt;
      &lt;/xsd:restriction&gt;
    &lt;/xsd:simpleType&gt;
  </code></pre>
  
  <p>Generated reference -</p>
  
  <pre><code>[System.Diagnostics.DebuggerStepThroughAttribute()]
  [System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "4.0.0.0")]
  [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Advanced)]
  [System.ServiceModel.MessageContractAttribute(WrapperName="isPermissableRq", WrapperNamespace="http://contracts.co.za/TransactionMgmnt", IsWrapped=true)]
  public partial class isPermissableRequest {
  
      [System.ServiceModel.MessageHeaderAttribute(Namespace="http://contracts.co.za/Infrastructure/2008/09/EnterpriseContext")]
      public Services.Svc2014.EnterpriseContext_Type EnterpriseContext;
  
      [System.ServiceModel.MessageBodyMemberAttribute(Namespace="http://contracts.co.za/services/2014-12-16/TransactionMgmnt", Order=0)]
      public string accNr;
  
      [System.ServiceModel.MessageBodyMemberAttribute(Namespace="http://contracts.co.za/services/2014-12-16/TransactionMgmnt", Order=1)]
      public long bankNr;
  
  
      public isPermissableRequest() {
      }
  
      public isPermissableRequest(Services.Svc2014.EnterpriseContext_Type EnterpriseContext, string accNr, long bankNr) {
          this.EnterpriseContext = EnterpriseContext;
          this.accNr= accNr;
          this.bankNr = bankNr;
      }
  }
  </code></pre>
  
  <p>When I add a service reference using vs 2013, i expect a specified field to be generated for bankNr, since minOccurs is 0, but that does not happen. Any ideas? This field needs to accept a null.</p>