How to change buscomp sortspec?

Hello all,

Can anyone help me with the below:

Context:Strange behavior with custom buscomp (copy of standard Campaign List Contact) based on table S_CAMP_CON.

Steps:

1. Created buscomp(class cssbuscomp)

2. Add it to Campaign BO and custom View.

ISSUE: Custom buscomp doesn't have any view modes, user property, etc. SQL is always generated with Sort spec on columns TARGET_NUM and POSTN_ID
The requirement is to put custom sort spec based only on column TARGET_NUM.
So, the problem is - Changing buscomp sortspec based on S_CAMP_CON table doesn't affect sort order (always adding column POSTN_ID).