How to configure a custom PropertySearchManager for a repository manager

All,

I am trying to configure a PropertySearchManager for my customRepositoryManager. I have defined in my.co.xml, the value for the property search manager class. <i><b><property name="propertysearchmgr.class" value="MyPropertySearchManager"/></b></i>. But after I deploy my par to the server, when I go to System configuration-Knowledge Management-content Management-Repository Managers, I cannot see MyPropertySearchManager in the pick list for PropertySearchManager.

Any idea why? How can I configure MyRepositoryManager to use MyPropertySearchManager?

Thanks,

Seema