GUI.Texture Over GUI.Window

hi~ i’d like to ask how can a GUI.Texture() be drawn over GUI.Window() on the same script

e.g

function OnGUI()
{
 GUI.DrawTexture(Rect((mX-msX/2),((Screen.height-mY)-msY/2+msY/2),msX,msY),cmTex);//texture

 bag = GUI.Window(0,bag,bagWindow,cPage[gridV]); //window
}

Try like this ;

funtion OnGUI()
{

GUI.Window (0, windowRect, GUI.WindowFunction (DoWindow), "Window");

}

function DoWindow (windowID : int)
{

GUI.DrawTexture(Rect((mX-msX/2),((Screen.height-mY)-sY/2+msY/2),msX,msY),cmTex);//texture

}