Tested an appliance upgrade from 5.6.0.9 to 5.6.0.11 via Admin UI, RHN registered and a custom repo for the 5.6.0.11 bits, Admin UI configured with external auth to IPA. After the upgrade, Settings->Configuration->Region->Red Hat Updates shows the new 5.6.0.11-rc.2.2 version and was able to login using the IPA credentials. Could be an issue on 5.5 only, will need to test there separately.