I can't answer the "why", but I had the same problem. I worked around it by putting the @Column annotation in the Primary Key class. | public class Foo { | | @Id | public Long getFooId() { | } | | @Id | public Long getBarId() { | } | | public static class FooPK { | | @Column(name="FOO_ID") | public Long getFooId() { | } | @Column(name="BAR_ID") | public Long getBarId() { | } | } | } | Seems to have given me the result I needed. But I'm not sure how this will affect future mappings, annotations, etc. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4032406#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...