Downgrading an application

For the first time in my career I'm working on downgrading an application. We worked for about 7 months on an application where persistence is handled by Hibernate. Due to some license/patents issues with our partner it was decided to migrate the persistence layer to EJB3.0/JPA using the container provided JPA implementation(the application is supposed to be deployed on various application servers - WebSphere and WebLogic for sure - depending on the client). The problem is that the EJB 3.0 standard is less powerful than Hibernate and also the implementation is in version 1.0 (for example WebSphere uses OpenJPA from Apache which is in version 1.0.2) which means missing features and bugs, so this migration turns out to be a downgrading of the application :(