You can implement a custom adapter that parses your special date format string into a valid date. 
    package xmlhelper;
    
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    import javax.xml.bind.annotation.adapters.XmlAdapter;
    
    public class DateAdapter extends XmlAdapter<String, Date> {
    
    	private SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy");
    
        @Override
        public String marshal(Date v) throws Exception {
            return dateFormat.format(v);
        }
    
        @Override
        public Date unmarshal(String v) throws Exception {
        	return dateFormat.parse(v);
        }
    }
To use it in your webservice you have to modify the generated webservice source class. Simply add an `@XmlJavaTypeAdapter` annotation into your method parameter definiton:
      @javax.jws.WebMethod
      @javax.jws.WebResult(name="result")
      public CallResult call(
    		  @javax.jws.WebParam(name="createJavaDataSaved") 
    		  @XmlJavaTypeAdapter(DateAdapter.class) 
    		  java.util.Date createJavaDataSaved)
        throws ch.ivyteam.ivy.webservice.process.restricted.WebServiceProcessTechnicalException
      {
        ...
      }
Remember that the generated webservice source will be overwritten whenever you change the mod file of the webservice. So you should at least write a test against your webservice stub so that you get an early warning if the adapter is not in charge anymore.
![alt text][1]
You can inspect a full sample implementation here: [webserviceProviderWithSpecialDateFormat_63.iar][2]
  [1]: http://answers.axonivy.com/upfiles/soapUiCallWithSpecialDateFormat.pnghttps://answers.axonivy.com/upfiles/soapUiCallWithSpecialDateFormat.png
  [2]: http://developer.axonivy.com/q-and-a-attachments/webserviceProviderWithSpecialDateFormat_63.iar/upfiles/webserviceProviderWithSpecialDateFormat_63.iar