add own code to nopcommerce

Hello all,

I have added 1 aspx and 1 empty according user control like this:
<%@ Page Language="C#" MasterPageFile="~/main.master" AutoEventWireup="true" CodeFile="OgoneSHA.aspx.cs"
    Inherits="NopSolutions.NopCommerce.Web.OgoneSHA" %>

<%@ Register TagPrefix="nopCommerce" TagName="Blog" Src="~/Modules/OgoneSHA.ascx" %>
<asp:Content ID="Content1" ContentPlaceHolderID="cph1" runat="Server">
    <nopCommerce:OgoneSHA ID="ctrlOgoneSHA" runat="server" />
</asp:Content>

Now i get: Unknown server tag 'nopCommerce:OgoneSHA'.

What needs to be done to get it working? Is this documented?
Thanks

<%@ Register TagPrefix="nopCommerce" TagName="Blog" Src="~/Modules/OgoneSHA.ascx" %>
<asp:Content ID="Content1" ContentPlaceHolderID="cph1" runat="Server">
<nopCommerce:Blog ID="ctrlOgoneSHA" runat="server" />
</asp:Content>

In this syntax <nopCommerce:Blog ID="ctrlOgoneSHA" runat="server" />
Can you please subscribe in a few lines how do I change words
a: nopCommerce
b: Blog

Thanks

<%@ Register TagPrefix="Whatever" TagName="YouWant" Src="~/Modules/OgoneSHA.ascx" %>

<asp:Content ID="Content1" ContentPlaceHolderID="cph1" runat="Server">
<Whatever:YouWant ID="ctrlOgoneSHA" runat="server" />
</asp:Content>