Go to the Configuration tab> Server Settings > Notification Server Infrastructure > Task Server > Task Types, right-click on Properties and choose Security tab and then Add the desired role.
The role will need to be given at least Read under Altiris System Permissions and Create New Task under Altiris Task Permissions.
There are some other permissions to be aware of. You can set the appropriate permissions to create the tasks, but if you attempt to configure them, you may not be able to apply them to collections or computers. In order for the UI to properly display the resources to select collections or computers to apply tasks to, the correct permissions must be set on the resource management tab as well. The list of permissions is below. This is not a minimum list, based on the breadth of jobs that Task Server can complete. These permissions can be reduced, based solutions installed, and job/task requirements. Set the following permissions on the Resource Management Folder:
Altiris Collection Permissions: Run Task On Collection, Apply Agent Settings, Apply Software Delivery Tasks
Altiris System Permissions: Read, Read Permissions
Altiris resource management Permissions: Read Resource Data, Read Resource Association, View Password
Sequential Software Delivery Task Permissions: Apply to Collections, Install on Approval, Install Software
Asset Permissions: Report on Owner Resources
Altiris Report Permissions: Run Reports
Software Migration task Permissions: Apply to Collections
Altiris Task Permissions: Create New task, Run task, Apply to Collections
Software Portal Permissions: Install Software
Software Update Management Permissions: Apply Software Update Tasks
Notification Server 6.0.6074
Task Server 6.0
Applying Security Roles with less than Altiris Admin rights