Hi There,
Forgive me if im misunderstanding the question, but if you are looking for a list of activities associated with a particular customer, this is already a part of Method! You can view these activities by navigating to your Customers and Contacts List (Under the Customers tab) and selecting Go to... beside the customer you are wanting to view the activites for. On the Edit customer screen which you are taken to, you will see in the bottom section of the screen an Activities tab which, when clicked on, will show you a full list of every activity associated with that customer.
Thanks! Let me know if I can be of any more assistance.
Regards,
Ben