Query on field of embedded object - "Unknown state or association"

Question

I'm trying to define a query which selects entities on the basis of a field nested in an embedded field of the entity class.
The query looks like:
select inv from Invoice inv where inv.weekNo.year = :year AND inv.weekNo.weekNo = :week AND
inv.member.id = :memberCode
where:
    @Embedded
    public BusinessDate getWeekNo() {And the BusinessDate class has a year and weekNo field defined for persistence.
The result is :
Exception Description: Unknown state or association field [year] of class [com.cc.ei.model.data.BusinessDate].
Hibernate compiles this query OK but toplink rejects it.
What I'd like to do is put this under the Member entity as a filtered query (I need Invoices for a specific week for a given member) but there's no @Filter in the javax.persistence stuff, that I can find.

Answer 1

Toplink essentials.
The year attribute is simply an integer field, mapped to a "YEAR_NUMBER" column.
The @Filter I'm talking about is an extra facility in Hibernate annotations (outside of the javax.persistence stuff). The idea is that when you've got a one-to-many relationship you don't always want every child record, in this case, for example, I want the invoices under a Member limited to a specific business week (matching week number and year).
It's not very elegant to have to, effectively, ignore the existing relationship and use a stand-alone Query.
As to the original problem I've concluded the best way is probably to put the year and week number fields in the Invoice entity separately, and build my BusinessDate object from them. Using BuisnessDate as an embeddable would have been more elegant, but it's not the end of the world.