Activity Create security access right

Hi,

I have a client and they want their agents to be able to read activities, but not create them from CRM directly. I thought it would be a good idea to remove the "create" right from security roles on activities. Altough I removed the roles, it is still possible to create an activity.

I was expecting to see that all "new activity" functionality would be removed.

Any ideas?

many thanks,

cem