<%@ Page language="C#" %>
<%-- we can even override the asp prefix with @ register --%>
<%@ Register TagPrefix="Acme" namespace="System.Web.UI.WebControls" assembly="System.Web" %>
<%@ Register TagPrefix="Acme" TagName="One" Src="registertest1.ascx" %>
<%@ Register TagPrefix="Acme" TagName="Two" Src="registertest2.ascx" %>

<html>
