accessing web service problem

I'm developed web service from java class. Then, portal project with portal service(client side).

And at last, I'm developed portal aplication in witch I want to use my web service through portal service

I'm create PrivateSharingReference: <property name="PrivateSharingReference" value="SAPJ2EE::CalculatorSRV"/>

The resut was: java.lang.NoClassDefFoundError: com/sap/webservices/myservices/calculator/SumThis

Then I try: <property name="PrivateSharingReference" value="SAPJ2EE::service:CalculatorSRV"/>

The result is: com.sapportals.portal.prt.core.broker.ExternalApplicationNotFoundException: Could not find portal application SAPJ2EE::service:CalculatorSRV

ps. CalculatorSRV - the name of the portal service

How can I solve this problem??