We can do this with our new Participant feature added to our updated Reporting Suite. The step by step details for our best practices to attendance and using Participant Groups can be found here (note this will require one of our plans which comes with Reporting features):

http://polleverywhere.uservoice.com/knowledgebase/articles/685605

Otherwise, the basics are;

1. Have all of your students in Participant Groups based on class
2. set your poll questions to registered participants only
3. run a Gradebook report on all of the polls you are using for attendance
4. To the right of the Gradebook report > select the Participants menu > and chose the participant group (class) that you want to report on. It will include all students who are in this group, but did not responsd