Issue with using relations between two external tables

Hi,

I am using two external tables Article and ArticleAttribute and made a relation between them. On the Article page I added a grid component for ArticleAttribute and on ArticleAttribute page a lookup to Article. I have a problem saving the Article when there are ArticleAttributes linked and also when saving an ArticleAttribute whith Article set. An error is raised:

ERROR: Error in query SELECT NAME, PRODUCTID, PRODUCTSTATUS, PRODUCTTYPE FROM ARTICLE WHERE null=?: RB_179: Error preparing statement for query SELECT NAME, PRODUCTID, PRODUCTSTATUS, PRODUCTTYPE FROM ARTICLE WHERE null=? [DataDirect][OpenEdge JDBC Driver][OpenEdge] Syntax error in SQL statement at or about "null=?" (10713)

I suppose this error is raised because the foreign key is not identified. Did anyone had this issue?

Thanks