jpramac,
You need to add schemaname.sequencename / databasename.sequencename for the sequenceName attribute under @SequenceGenerator annotation to get it working.
Here is the code that I added in my domain (POJO) class and got it working :
@Id
@Column(name = “id”, nullable = false, unique = true)
@Basic(fetch = FetchType.EAGER)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator=”my_seq”)
@SequenceGenerator(name=”my_seq”,sequenceName=”TestSchema.DEPT_SEQ”,allocationSize=1)
@XmlElement
Integer id;
Let us know how it works for you.