Again Feedback Problem

Hi, i am still working on feedback…
my problem is, when i am using glortho, i dont get the vertex- values only by using glPerspective()…
can somebody pls take look at my code:


 public void vertexFeedbackMode(Vertex v){
		//System.out.println("start vertexFeedbackMode()");
		FloatBuffer feedbackBuffer = BufferUtils.newFloatBuffer(1024);
		int size;
		
		Vertex vertex = v;
		
		gl.glFeedbackBuffer(1024, GL.GL_3D, feedbackBuffer);
		gl.glMatrixMode(GL.GL_PROJECTION);
		gl.glPushMatrix();
	
		gl.glRenderMode(GL.GL_FEEDBACK);
		gl.glLoadIdentity();
		

               // glu.gluPerspective(45.0,this.h, 1.0, 20.0);
		
		gl.glOrtho(0.0,(double)screenwidth,0.0,(double)screenheight,-1.0, 1.0);

		//
	//	gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	//	gl.glClear(GL.GL_COLOR_BUFFER_BIT);
	
		 

		//gl.glTranslatef(0.0f, 0.0f, -6.0f); 
	
		
		gl.glPassThrough(1.0f);
		
		gl.glBegin(GL.GL_POINTS);
		  gl.glVertex3f(vertex.data[0],vertex.data[1], vertex.data[2]);	
		  gl.glEnd();
		  
		size = gl.glRenderMode(GL.GL_RENDER);
	
		printOutFeedback(size, feedbackBuffer);
		 gl.glMatrixMode(GL.GL_PROJECTION);
	        gl.glPopMatrix();
	        gl.glMatrixMode(GL.GL_MODELVIEW);
	        gl.glLoadIdentity();
		//System.out.println("end vertexFeedbackMode()");
	 }