you point me in the right direction !!!!
my mistake, I overdo something...
following your guide, I install rpmforge and epel repositories
I put different priorities to every repository , instead of only put epel in priority 10
and that was my problem, after that yum install amavis and some packages from rpmforge instead of epel
I remove the priorities , run yum update and voila!! everything works according to your guide
thanks for everything