I blogged last week on the importance of backing up your Tivoli Enterprise Portal Server. I do think it's easy, especially in a z centric environment, to overlook the necessity of backing up this component.
One reader mentioned that they use the migrate-export script provided by IBM to handle the backup of the TEPS database. This is certainly a valid way to do it, and if you are unfamiliar with the process here is a link to the doc:
You have other options, as well. Don't forget about the TACMD command that I've blogged about earlier. The TACMD provides a mechanism to export things like workspaces to XML, and then importing these components.