allocate budget to PPM bucket

SAP-PPM 6.0

How do we allocate budget to PPM bucket?

The scenario we are replicating is:

- Planned values, bottom-up. This means, financial planning/forecast will be done at Item level and the total will roll up to the bucket

- The budget needs to be approved at the bucket level so that the allocation (to items in the bucket) is top-down

Additionally, is it possible in PPM 6.0 to

- move unused budget in the Item back to the bucket?

- move unused budget at the bucket level to some other bucket or some other fin period?

- how about availability control? How can we view the remaining budget at the Item and Bucket level?

Thanks much for your time...