Bug 154803 [regression]Cannot render document to user defined path through __document parameter
Description: Cannot render document to user defined path through __document parameter Steps to reproduce: 1. Preview a report in viewer 2. Modify url to add "__document=c:/tmp.rptdocument", this will generate report document to c disk with name "tmp.rptdocument" 3. Press enter. Expected result: Report displays correctly and the document is created. Actaul result: The document file : c:/tmp.rptdocument does not exist or contains errors.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
if ( defalutValue == null && parameter != null )
		{
			defalutValue = parameter.getDefaultValue( );
		}
		return defalutValue;
	}
	/**
	 * if parameter existed in config file, return the correct parameter name
	 * 
	 * @param configVarName
	 *            String
	 * @return String
	 */
	private String getParameterName( String configVarName )
			throws ReportServiceException
	{
		String paramName = null;
		
		List parameters = getParameterList( );
		if ( parameters != null )
		{
			for ( int i = 0; i < parameters.size( ); i++ )
			{
				ScalarParameterHandle parameter = null;
				if ( parameters.get( i ) instanceof ScalarParameterHandle )
				{
					parameter = ( (ScalarParameterHandle) parameters.get( i ) );
				}
				
				String curName = null;