[Fedora-packaging] disttag doesn't work

[Martial Paupe]

hello,

I'm building packages and I want to use disttag as referred at this page.

https://fedoraproject.org/wiki/Packaging:DistTag

as a result the package is named as is

packagename-1.0.0-1.noarch.rpm instead of
packagename-1.0.0-1el5.noarch.rpm

here the head of my specfile.

Name:          packagename
Version:        1.0.0
Release:        1%{?dist}
Summary:      some text  

Group:          application
License:        Propriatory
URL:            http://somewhere.domain.com
Source0:        %{name}-%{version}.tar.gz
BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
BuildArch:      noarch
Conflicts:      libgcj

%description
more text in these area

%package binary
Summary: packagename binary and library
Group: System

%if 0%{?rhel} >= 4 || 0%{?rhel}
Requires: jre
else
Requires: java-1.6.0-openjdk
Obsoletes: jre
%endif
Obsoletes: packagename-stack
......
......
......
......

What I do wrong? Thanks for your help