OrderBy Issue in Hibernate

I try to generate query using EntityManager.createQuery for my ORM mapping classes. In the resulted query order by include primary key field of the class by default even though I have specified two fileds to order by in @OrderBy ("sequenceOrderNo asc, nextXpath asc "). Please any one advice me how to remove the default primary included in order by clause of the generated query. I am looking the for this solution for more than 4 days. Experts pls help me.

I have used below in my project

DB: Oracled 10g
openjpa 2.0 jar