[CentOS] updating libvorbis

Hello,

On a machine with CentOS-5.6, I need libvorbis >= 1.2, so I have 
recompiled and packaged libvorbis. 
But I get the following error :

$ rpm -U /usr/src/redhat/RPMS/x86_64/libvorbis-1.2.3-phn.1.x86_64.rpm /usr/src/redhat/RPMS/x86_64/libvorbis-devel-1.2.3-phn.1.x86_64.rpm
        package libvorbis-1.1.2-3.el5_4.4.x86_64 (which is newer than libvorbis-1.2.3-phn.1.x86_64) is already installed
        package libvorbis-devel-1.1.2-3.el5_4.4.x86_64 (which is newer than libvorbis-devel-1.2.3-phn.1.x86_64) is already installed

Who knows how to make rpm understand than 1.2.3 is newer than 1.1.2 ?
I have tried :
%define name libvorbis
Name:		%{name}
Provides:	%{name} = %{version}-%{release}
Obsoletes:	%{name} < %{version}-%{release}
and the same thing for %{name}-devel, but without any success.

"Yum update" also fails, with the following error :
Examining /usr/src/redhat/RPMS/x86_64/libvorbis-1.2.3-phn.1.x86_64.rpm: libvorbis-1.2.3-phn.1.x86_64
/usr/src/redhat/RPMS/x86_64/libvorbis-1.2.3-phn.1.x86_64.rpm: does not update installed package.
Examining /usr/src/redhat/RPMS/x86_64/libvorbis-devel-1.2.3-phn.1.x86_64.rpm: libvorbis-devel-1.2.3-phn.1.x86_64
/usr/src/redhat/RPMS/x86_64/libvorbis-devel-1.2.3-phn.1.x86_64.rpm: does not update installed package.
No Packages marked for Update

Can someone help me ?

Thanks,

-- 
Philippe