Bug 156642 [Regression]Script of onPrepare is no effect
Details: Script of onPrepare is no effect Set any function on onPrepare, but it is no effect. For example: this.getStyle().color="red" Excepted: it is effect
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/RunAndRenderTask.java
if ( !supported )
		{
			log.log( Level.SEVERE,
					MessageConstants.FORMAT_NOT_SUPPORTED_EXCEPTION, format );
			throw new UnsupportedFormatException(
					MessageConstants.FORMAT_NOT_SUPPORTED_EXCEPTION, format );
		}
		IContentEmitter emitter = null;
		try
		{
			emitter = extManager.createEmitter( format, emitterID );
		}
		catch ( Throwable t )
		{
			log.log( Level.SEVERE, "Report engine can not create {0} emitter.", 
					format ); 
			throw new EngineException(
					MessageConstants.CANNOT_CREATE_EMITTER_EXCEPTION, t );
		}
		if ( emitter == null )
		{
			log.log( Level.SEVERE, "Report engine can not create {0} emitter.", 
					format ); 
			throw new EngineException(
					MessageConstants.CANNOT_CREATE_EMITTER_EXCEPTION );
		}
		return emitter;
	}
	private void initializeContentEmitter( IContentEmitter emitter,
			ReportExecutor executor )