Yes you can, that's why you have access to the task compoment as a separate entity.
You will need to create the relationships with the process id if you want to keep track that those tasks where created for a specific process instance or you can keep track of those dynamic tasks using your business entities.
I've created an example where I create dynamic tasks without even using a business process. that probably can help you out to understand how to implement your situation:
http://salaboy.wordpress.com/2011/06/14/ad-hoc-human-tasks-for-monitoring-like-systems/
Cheers