Baseline feature for Financial planning

We would really appreciate a baseline feature for the financial planning module/view.

We plan our projects ahead of time and have to submit our quarterly costs of the project (project 3 month periods, not calendar quarters). As we don't always know in advance who will be actually doing the task we use placeholder resources with average cost to do the plan.

When we now come to actually running the project we will obviously replace the resources with the actual resources and their cost. at which point the budget cost will change. It would be great to baseline it before we go live to then see whether we are going over or under the proposed time-phased labour budget.

Thanks a lot