Bug 182680 Use feature of new Aggregation framework of Data Engine.
DataEngine will implement new aggregation framework in 2.2.0RC0. After the implementation is finished Engine should go ahead to use new column bindings in definition of map/highlight.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/GetParameterDefinitionTask.java
* parameter to work on will be the third level which is City in "USA, CA"
	 * in this case.
	 * 
	 * @param parameterGroupName -
	 *            the cascading parameter group name
	 * @param groupKeyValues -
	 *            the array of known parameter values (see the example above)
	 * @return the selection list of the parameter to work on
	 */
	public Collection getSelectionListForCascadingGroup(
			String parameterGroupName, Object[] groupKeyValues )
	{
		CascadingParameterGroupHandle parameterGroup = getCascadingParameterGroup( parameterGroupName );
		if ( parameterGroup == null )
			return Collections.EMPTY_LIST;
		SlotHandle slotHandle = parameterGroup.getParameters( );
		if ( groupKeyValues.length >= slotHandle.getCount( ) )
		{
			return Collections.EMPTY_LIST;
		}
		for ( int i = 0; i < groupKeyValues.length; i++ )
		{
			String parameterName = (( ScalarParameterHandle ) slotHandle.get( i )).getName( );
			setParameterValue( parameterName, groupKeyValues[ i ] );
		}
		ScalarParameterHandle requestedParam = (ScalarParameterHandle) slotHandle
				.get( groupKeyValues.length ); 
		
		
		if ( requestedParam == null )