无法将java.lang.Integer字段id设置为org.hibernate.id.IdentifierGeneratorHelper

I need to store some data in a MySQL-database using Jpa 2/Hibernate 3.5.1. For legacy reasons the table I want to store data in has a compound primary key. The first part of the primary key is of type INTEGER (auto-increment-value), the second part is of type BIGINT (Long in Java-code - to be set manually before persisting).I need to store some data in a MySQL-database u