FWIW, the JPA module (or modules...I've seen a handful of implementations out there) are not yet part of Spring Social itself and are community-led efforts. Therefore, I've not had opportunity to try them out.
That said, if I were you, I'd probably start with something like the Spring Social Twitter4j sample (https://github.com/SpringSource/spri...cial-twitter4j) and swap out the JDBC connection repositories for the JPA repositories. I suggest this because the Twitter4j-based sample uses XML configuration already.
If you're willing to work with cutting-edge snapshot code (e.g., 1.1.0.BUILD-SNAPSHOT), I'm planning to work up a clone of the Spring Social Showcase project that is configured in XML. It may be a week or so before I get it out there, but it may also prove useful as a starting point where you can swap out JDBC-based connection repositories for JPA-based connection repositories.
Spring Social Project Lead