Scroll in a long text GUILayout.TextArea

Hello, I'm going crazy, I can not find the solution .... I'm trying to make a telnet client to a MUD. I need a window containing the text I receive from Socket. I am using GuiLayout and TextArea:

   GUIStyle aStyle = new GUIStyle();
   aStyle.fontSize = _GUIFONTSIZE_;
   aStyle.normal.textColor = Color.white;
   aStyle.richText = true;
   aStyle.font = PromptFont;
   aStyle.wordWrap  = false;
                     
   GUILayout.BeginArea(new Rect(0, 0, _GUIWIDTH_, (_GUIHEIGHT_-25)));
                     
   scrollPosition = GUILayout.BeginScrollView (
   scrollPosition, false, true, GUILayout.Width (_GUIWIDTH_), GUILayout.Height(_GUIHEIGHT_-25));        
                 
   GUILayout.Label (rcvBuff.ToString(), aStyle, GUILayout.ExpandHeight (true));
             
   GUILayout.EndScrollView ();
                 
   GUILayout.EndArea();

It works ok but when the text is too long the scroll does not grow. What could it be?.