o there is a subtle realm problem with plexus and under certain conditions (release deploys) the wagon manager used to populate auth info is not the same as used by the wagon manager. this is fixed in subsequent releases of plexus but i'm not testing everything again so i'm using a static map as a work around. when alpha-1 is released i'll bump the version of plexus and test again.
maven/components/trunk/maven-compat/src/main/java/org/apache/maven/artifact/manager/DefaultWagonManager.java