There is no relationship between those two. They are two different ways of managing the work. the Agile Workbench is more of an Agile way of handling requirements in terms of Feedback, User Story and Bugs associating to features of the application.
So how do we manage the user stories captured in DCO through the Agile workbench? If stories have been captured in DCO should they be re-entered into the agile workbench to manage them during the sprints?
As there is a user story category within the DCO tool as well, shouldn't they be directly visible in the agile workbench as well?
There is no way to link the requirements or specifications added in the DCO to AWB.
I guess Pega is trying to move away from the traditional DCO process to a more Agile way. To support this, they have allowed for creation of Features instead of requirements and specifications. These features can be directly link to the user stories in AWB. This is more in line with how you create Requirement Artifiacts in Agile: EPICS(Can be interchanged with Features)-->User Stories-->Acceptance Criteria