Personalization to remove ability to update/create tasks in PJMT OAF Pages

 Reqmt is to personalize the PJMT OAF page, Task Detail page(at Responsbility level) so that the 

1.Users should not be allowed to update task numbers

2.User should not be able to create new tasks 

The first one is  easier, since we can set the task number text field to display only through personalization

For the second part through OAF Personalization can I remove Create Tasks,Cancel Tasks from the drop down list in the Task Detail Page ? So that users from can not select these actions and 

Or is there a better way to do this?

Appreciate any inputs/pointers.