Override Page.Title ?

I've got a class wich overrides the Web.ui.page.
But i try to hange the title, so its the same on every page, but it doesnt work :(.
The code is run: but it seems to be empty on the default.aspx..

How can i do this ?
this is my code: 

public class PageOverride : System.Web.UI.Page
{

    public PageOverride()
    {
        Page.Title = ConfigurationManager.AppSettings["SiteName"];
    }

...