Thank you for using our services.
Unfortunately the Comments functionality can not be integrated with the Polls module as it is. The Comments functionality is part of Generic Cotnent Based modules and he Polls Module is not GC based module. This means that if you wish to add comments you will have to develop your own functionality. You can use Linq for developing your data layer and then you should override the PollBox control in order to add your comments functionality and tie up comments with a particular poll.
For more information you can check out:
Implementing Data Access with LINQ to SQL
Polls API Overview
Just to let you know that in Sitefinity 4.0 Comments will be a plug-in and it will be possible to associate it with any type of content - pages, content items, etc.
the Telerik team