Attaching a custom form from WF to a PHQ proof

I would like our designers to be able to attach a custom form with the project details to the proof. We do all our approvals in PHQ, so our reviewers never log in to WF. The form provides the market and content context to the document we are asking our reviewers to comment on. The reviewers are cross-organizational and cross-functional, so they don't have access to this information any other way. Thanks.