The link quoted on the EclipseLink/Maven wiki ends on an Error 403 page on switch.ch. If you are redirected to a better mirror then that would already be the answer.
All broken. I get 404s everywhere. And the Nexus instance has not indexed the latest releases. Thank you very much for chaotic distribution managment (the project should really be relocated to Apache)
However, manual digging lead to:
org.eclipse.persistence
javax.persistence
2.3.2
compile
EclipseLink Repo
http://maven.eclipse.org/nexus/service/local/repositories/Sonatype/content
Again, this is not working 100% perfectly because Maven is not able to find dependency information.
Hmmm... maybe I should think again before using software that is obviously maintained in such an amateurish manner.