Problem with VO Extension (Urgent.......)

Question

Hi,
I extended one VO which is not based on any VO. Is it mandatory to add the new VO to the Application module which the old VO is referencing?
The problem is when I am wirting the where clause to the new VO, I am not getting any error but my VO has not filtered with my where clause.
I written the code in my CO as:
//for getting the VO reference
CopyLibraryTestVOImpl libVo=(CopyLibraryTestVOImpl)oaapplicationmodule.findViewObject("CopyLibraryTestVO");
//set the where clause
libVo.setWhereClause("ATTRIBUTE2 = :1");
                         libVo.setWhereClause("ATTRIBUTE4 = :2");
                         libVo.setWhereClause("ATTRIBUTE6 = :3");
libVo.setWhereClauseParams(null);
libVo.setWhereClauseParam(0, len1);
libVo.setWhereClauseParam(1, len2);
libVo.setWhereClauseParam(2, len3);
libVo.executeQuery();     
============================================
Can any one help me on this issue.
Thanks,
Satya.

Answer 1

For substitution you need to follow a few steps which I am not sure whether you have done or not.
libVO might be coming as null because you haven't added it to any AM.
--Shiv