I don't believe we've ever hosted the agent packages separately on our repositories. There are deb and rpm packages for the agent bundled inside the opscenter package itself; perhaps these are what you were using?
Also note that when OpsCenter starts up for the first time, it generates files used for SSL communication with the agent. These are then put into an agent tarball (to support users who want to install the agent manually) and installed directly when OpsCenter goes through its normal agent installation routine. If you want SSL to be enabled, you will also need to copy the files from the "ssl" directory on the opscenterd machine (/usr/share/opscenter/agent/ssl if working from a package install) to the "ssl" directory on the agent machines (/var/lib/opscenter-agent/ssl/).