How to enable the publishing of User DNs
Check (/opt/glite)/etc/glite-apel-publisher/publisher-config-yaim.xml and see if you have <JoinProcessor publishGlobalUserName="yes"> configured. If not, change it.
Set APEL_PUBLISH_USER_DN=yes, in your YAIM configuration files, so that the next APEL YAIM reconfiguration preserves the <JoinProcessor publishGlobalUserName="yes"> definition