http://dev.bukkit.org/server-mods/limited-creative/
Download and install xAuth and Multiworld into the local repo repository with a command like so:
mvn install:install-file -Dfile=xAuth-2.0.26.jar -Dpackaging=jar -DlocalRepositoryPath=repo -DgroupId=de.luricos.bukkit -DartifactId=xAuth -Dversion=2.0.26