I want to show some panel with a label that is located on a MasterPage from inside it's child pages.. I already did the coding on the MasterPage:

public class MyMaster : MasterPage
{
     public void ShowPanel(string pMessage)
     {
          labelInside.Text = pMessage;
          myPanel.visible = true;
     }
}

Then I make the calls from child pages:

public void ShowPanel(string pMessage)
{
     MyMaster masterPage = this.Master as MyMaster;
     masterPage.ShowPanel(pMessage);
}

This "works" ok, but it won't show nothing, since I need the page to be "refreshed" in an "ajax-way" like an UpdatePanel, which I can't use because the Trigger is in another page, right?

I really need this to work.. even if you have another completely different way to do this, I would appreciate.