Beaker specific post-installation scripts in kickstart log into /dev/console. This isn't true in case of custom kickstart defined via <kickstart/>. Appended beaker specific scripts do not have --log defined.
This is made slightly more awkward by the fact that RHEL3 does not support --log so we have to put the scriptlet in a subshell and redirect it for RHEL3. But it is still doable.
On Gerrit: http://gerrit.beaker-project.org/1076
Beaker 0.9.0 has been released.