In the forthcoming Dynamics AX 2012 R2 CU6 release, we made a few tweaks to the project budgeting form. First, we enabled multi-line delete in both the cost and revenue grids (it was previously one-at-a-time). This makes it much easier to clear out and start over when you are creating your budget. The second thing we enabled is a function to copy cost lines into revenue lines during budget entry. Previously, revenue lines would only get created if you were copying from forecasts or an existing project. We added a button to the revenue lines that will copy the cost lines, applying apply the pricing rules.
Note that this will only work if you are budgeting a time and materials project. Revenue for a fixed price project is not directly related to the costs so it does not apply in this case.
As you can see above, you need to specify the quantities for the cost lines in the details form (project budget only requires you to supply a budget amount and category). A quantity is required so that we can apply the sales price logic. Once you have your cost lines, click the Generate from cost budget button and it will create the revenue lines.
Stay tuned as we have several more enhancements to this area coming in CU7.