query restrictions with id primary key element

[jamesjmp]

Hello,
by means of seam-gen I have a POJO with an id attribute. The id is in fact another POJO. All is ok according to the database.
I´ve defined a query in componentes.xml. It works properly:

 <framework:entity-query name="POJOView"
 ejbql="select pojo from POJO pojo">
 <framework:restrictions>
 <value>pojo.atb1 = #{object.atb1}</value>
 </framework:restrictions>
 </framework:entity-query>

But if I use a restriction wich access to an id attribute it returns no error but no elements, and there are elements indeed.(With standard sql that info is retrieved)
For example:

 <framework:entity-query name="POJOView"
 ejbql="select pojo from POJO pojo">
 <framework:restrictions>
 <value>pojo.id.atb2 = #{object.value}</value>
 </framework:restrictions>
 </framework:entity-query>

#{object.value} has a proper value for pojo.id.atb2, in the same way as #{object.atb1} has for pojo.atb1. All attributes have their public getters.

Is there something special that must be done for restrictions when accessing a pojo.id.attribute?
thank you!!