Customize of Standard BO class in SAP WCEM

Hi Team,

I am trying to customize one of the standard class  which belong to the module wec~comm~mc~customerinteraction~bo~sap.com and the package by name com.sap.wec.module.customerinteraction.rating.backend.impl.crm the class name is by name RatingReviewCRM.java here the class connects with CRM .

Below are the steps followed

     1. In the custom BO module created a new package .

     2.Added new xml file called backendobject-config.xml and referenced the standard backend object with the new Z_RatingReviewCRM.java

     3.Z_RatingReviewCRM.java extends RatingReviewCRM.java

     3.Overridden the method  in Z_RatingReviewCRM.java

Problem:

     Unable to build the dpu the build breaks because of the changes made.

Can Anybody faced simillar kind if problem please guide me through this issue .Appreciate your help in this regard.

Thanks

Santosh