site:deploy is broken

With Maven 2.2.1 and the maven-site-plugin 3.0, site:deploy is not working anymore. This can be reproduced with the simplest empty project, see attached pom.xml

The error that occurs is:
java.lang.NoSuchMethodError: org.codehaus.plexus.PlexusContainer.getContainerRealm()Lorg/codehaus/plexus/classworlds/realm/ClassRealm;
(complete stacktrace attached)

This is in reference to this mail thread: http://markmail.org/message/ilfbqb2vhiyo5os4

Attached are:

• pom.xml (simple empty project)
• settings.xml (minimal config necessary for deploy)
• output from "mvn -X site:deploy" ("mvn site" was run before)