Restrict users to create Activities

Hi All,

I want to Restrict users to access(i.e. Create, Edit and display) Activities. so i have tried to restrict users to create activities(Activity Transaction Types) by adding the Activity types in CRM_ORD_PR Authorization Object and in CRM_ACT i maintained but still users are able to create and edit the activities.

More over Marketing RRelated Activities are appearing in Sales Role and Sales Related acrtivities are appearing in Marketing Role.

So Some please tell me the Authorization Object so that i can restrict the Users to create and edit the Activities in Sales Business Role and Marketing Business Role.

Thanks and Regards,

Arun