Spring and Hibernate: Entity inheriting from another database Entity (an having mapped properties from the firstone) - database

Question

I'm trying to isolate some core entities from my project. The idea of this is to share the same users, roles, etc. between many applications.
So, I have this User entity structure from core application, using a database called core:
#Entity
public class MyUser implements UserDetails, Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#Column(unique = true)
private String username;
private String password;
private String salt;
#ManyToMany(fetch = FetchType.EAGER)
private Set<Role> roles;
private Boolean isAccountNonExpired;
private Boolean isAccountNonLocked;
private Boolean isCredentialsNonExpired;
private Boolean isEnabled;
...
}
On the other hand, I have this other entity from the final application, using a database called myapplication:
#Entity
public class Employee extends MyUser {
private static final long serialVersionUID = 1L;
#Type(type = "date")
private Date birthDate;
#Type(type = "date")
private Date marriageDate;
private Long employeeNum;
private Integer workHs;
#OneToMany
private List<Role> canAssignRoles;
}
I created two datasources and session factories in hibernate.cfg.xml, one for each database, but I cannot achieve the purpose.
How you can see, one entity is mapped to core database, and the other one is mapped to the myapplication database. The Employee entity has a OneToMany mapping to Role.
I have no idea of how to solve this. When Hibernate is creating the database entities, it raises an error when trying to create the entities for myapplication.