what makes searchscope visible in "Search with in" dropdown list?

Hi,

I have created a custom searchscope for groups.

How can I make it visible in All Distribution groups/All Security Groups Page?

I have ensured that

1. Searchscope visible for all users by adding appropriate  Usage Keywords to the search scope.

2. Given Non Admin and Admin filter permissions to filter the attribute that being used in search scope.

3. Modified the MPRs to make the attribute visible for all the users i.e.., All users can read that group attribute.

Is there anything I have missed out?

Thanks and Regards, Siva Kumar Balaguru