yum don't use imported gpg key's

[tuxmaster]

Hello,
I have import an gpg repo key via rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-bareos
rpm -qa|grep key will list it.
An rpm -K on an package of the repo will work:
rsa sha1 (md5) pgp md5 OK
But on every yum run, yum will import the key again.
How can I automatic import repo keys, so that yum and rpm can use it?