typedef enum _POLICY_AUDIT_EVENT_TYPE
{
         AuditCategorySystem = 0,
         AuditCategoryLogon = 1,
         AuditCategoryObjectAccess = 2,
         AuditCategoryPrivilegeUse = 3,
         AuditCategoryDetailedTracking = 4,
         AuditCategoryPolicyChange = 5,
         AuditCategoryAccountManagement = 6,
         AuditCategoryDirectoryServiceAccess = 7,
         AuditCategoryAccountLogon = 8
} POLICY_AUDIT_EVENT_TYPE;

Windows Vista Kernel Structures