Issue still present in 4.3.6.FINAL. Attached JUnit tests (Eclipse Maven project) for all three cases: using @Embeddedable/@EmbeddedId, using @IdClass, or the hibernate-own "only @Id" mechanism. Only the last one works.

@IdClass or @EmbeddedId fails if the nesting level is more than 2. (Witness the two tests for only a subset of the entities working.)

(BTW, the test example was derived from a real-world legacy database. Since I must use standards-compliant annotations in that project, the hibernate-own "only @Id" approach is not an option for me, and this issue is a showstopper.)