If you can't find what you believe necessary to do the job, perhaps you should inquire with Altera. I've found them quite helpful. Their doc's are somewhat murkier than XILINX' but there are definitely ways of doing what you apparently wish to do, and there are app-notes to show you how.

Whenever vendors such as Altera and others publish spec's such as the ones you mention, they are inundated with questions about those particular features. They try to minimize the noise-traffic by making as little hoopla over these features. Ask them a precise question, and I'd guess you'll get a precise answer.

RE