How to create a custom URI to a custom tag (taglib)

Question

I have a project "lib" with classes that are common to other projects. In the project "guestbook" I want to use the tags defined in lib.jar I think for that I need to create a URI for my custom tag, as the spring is:

<%@ taglib uri="http://www.springframework.org/tags" prefix="spring"%>

And so I did, with a link any of my site (note: 404 returns, as well as in spring)

<%@ taglib uri="http://mysite.com/tags" prefix="myTag"%>

The guestbook says it can not find that tag. But as he does with the spring? I need to do some mapping?

Edit:

lib.jar/META-INF/filtro.tld:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<taglib xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"
    version="2.1">


    <tlibversion>1.0</tlibversion>
    <jspversion>1.1</jspversion>
    <shortname>filtro</shortname>
    <uri>http://desenvolvimento.rokko.com.br/tags</uri>
    <description>Tags para Filtro Avançado</description>
    <info>Tags para Filtro Avançado</info>

    <tag>
        <name>filtro</name>
        <tagclass>br.com.rokko.lib.helper.FiltroTag</tagclass>
        <bodycontent>JSP</bodycontent>
        <info>Filtro</info>
    </tag>
</taglib>

Some jsp from guestbook:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib uri="http://www.springframework.org/tags" prefix="spring"%>
<%@ taglib uri="http://desenvolvimento.rokko.com.br/tags" prefix="filtro"%> <!--error-->
<%@page contentType="text/html" pageEncoding="UTF-8"%>

Answer 1

That's right!

It seems to be a bug in the IDE (SpringSource Tool Suite). It shows a red line, as an error. But it compiles and runs right.