Delivery time item/supplier for promised date in a blanket release

Hello,

Does someone know how to set-up in Purshasing a delivery time for an item/supplier that supplier had commited to fulfill?

The expected functionality would be an automatic Promised date based on this "delivery time" as the following equation shows:

Release promised date = PO approval date + delivery time set up

Also, would I need another module combined to Purshasing to make it worked?

Thanks to all

Danny Corbeil