SoapUI Pro inline request parameterization

Hello.

I have problems with importing Java JAR to SoapUI Pro 4.5.0 Beta. I wanted to use my methods in Test Request to add specific content in XML. Can someone help me please?

I tryed it out with simple JAR file:

Jar file name: MyLib
package: lib
class: ParameterUtils
simple method: setParams - returning String content

package lib;

public class ParameterUtils {
    
    public static String getParams() {
        String param = "something";
        return param;
    }
    
}

I placed this JAR file in "c:\Program Files\SmartBear\soapUI-Pro-4.5.0-Beta1\bin\ext" folder.

Restarted the SoapUI.

Now i have TestRequest with simple XML:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:mds="http://www.cpoj.cz/jip/xsd/mds/mds" xmlns:req="http://www.cpoj.cz/jip/xsd/mds/mds/partnercreate/req">
   <soapenv:Header/>
   <soapenv:Body>
      <mds:partnerCreate>
         <req:msg msgUid="cpas\ipcp_esp" msgType="msg_mds_partnercreate_req" msgSourceSystem="22" msgVersion="100" msgTargetSystem="0"  msgId="0">
            <req:msgParams/>
  ${=MyLib.lib.ParameterUtils.getParams()}
            <req:msgData>
               <req:systemModified> I want to place content here with groovy.</req:systemModified>
            </req:msgData>
         </req:msg>
      </mds:partnerCreate>
   </soapenv:Body>
</soapenv:Envelope>

I tryed ${=MyLib.lib.ParameterUtils.getParams()}, but its not working. Can someone help me please?