I'm trying to make a permission, to limit view some activities types (A user with a specific role can't view a some activities types)
I was checking the hook permissions but i don't find the way(version civicrm 4.4).
Any idea to focus this issue?
You can install the Activity Type ACL extension to do this.
There was a proposal for ACLs for Activities and Cases and an ACL Hook for Cases has been implemented but not yet for activities. See What is the status of the make it happen for permissions on activities and cases?.