import ru.bitel.bgbilling.plugins.cashcheck.server.bean.*;
import bitel.billing.server.contract.bean.*;
 
check = event.getCheck();
 
if ( event instanceof AddPaymentCheckEvent)
{
   payment = event.getPayment();
 
   check.addString( " " );
   check.addString( "Телематические услуги связи" );
   check.addString( "Договор №: " + payment.getContractTitle() );
   check.addString( "Абонент: " + payment.getContractComment() );
 
   // добавляем параметр договора
   int PARAM_ID = 3;
   ContractParameterManager bgParamMan = new ContractParameterManager( con );
   String paramVal = bgParamMan.getStringParam( event.getContractID(), PARAM_ID );
   check.addString( "Какой-то параметр договора: " + paramVal );
   check.addString( " " );
 
   check.addPayment( payment.getSumma(), payment.getContractTitle(), event.getPaymentDep() );
 
   check.addString( " " );
}

import ru.bitel.bgbilling.plugins.cashcheck.server.bean.*;
import bitel.billing.server.contract.bean.*;
import java.security.AccessController;
import javax.security.auth.Subject;
import bitel.billing.server.admin.bean.User;
import bitel.billing.server.admin.bgsecure.bean.UserLoginModule.UserPrincipal;
 
public User getCurrentUser()
{
   Subject subject = Subject.getSubject( AccessController.getContext() );
   if( subject != null )
   {
      for( UserPrincipal userPrincipal : subject.getPrincipals( UserPrincipal.class ) )
      {
         return userPrincipal.getUser();
      }
   }
 
   return null;
}

check = event.getCheck();
if ( event instanceof AddPaymentCheckEvent)
{
payment = event.getPayment();
check.addString( " " );
check.addString( "Договор №: " + payment.getContractTitle() );
int PARAM_ID = 1;
ContractParameterManager bgParamMan = new ContractParameterManager( con );
String paramVal = bgParamMan.getStringParam( event.getContractId(), PARAM_ID );
check.addString( "ФИО/Организация: ");
check.addString( paramVal );
check.addString( " " );
check.addPayment( payment.getSumma(), payment.getContractTitle(),0 );

Method getCheck() not found in class'bitel.billing.server.script.bean.event.PaymentEvent'