Hibernate version:
Hibernate 3.1beta3
Hibernate Annotations 3.1beta5
Hibernate Entitymanager 3.1beta3

Name and version of the database you are using:
embedded hsqldb

I am testing the Entitymanager in a j2se environment.

My class works with @Entity(access=AccessType.PROPERTY)
and @Id(generate = GeneratorType.AUTO).
However, if I switch to @Entity(access = AccessType.FIELD) annotation,
the ID Generator isn't called and I get a

org.hibernate.PropertyValueException: not-null property references a null or transient value:

Exception.

The hibernate create table sql statement etc. are the same as the PROPERTY annotation.

Does anybody have a similiar problem ?"

I'm using AccessType.FIELD all over the place, but never the GeneratorType.AUTO. Just one thing: make sure you put the @Id annotation right before the member field (as opposed to the getXXX method).

I think it makes no difference which GeneratorType I use
as the generator is used with PROPERTY annotation.

And yes I'm sure that I put all annotation for both tests in the right place.

I'm using other annotations (@Colum(nullable = false, length = ....) etc. and all this annotations are ok with FIELD and PROPERTY annotation.

The only problem is, I didn't get an ID if I use FIELD annotation.

Post your code... it might be a simple oversight.