If you want to purchase items directly for some Job, you can do it using e.g. Purchase Order and posting it. Flowchart of posting groups usage is the same as in post I already wrote about item purchase posting. There is only one additional step in comparison with standard item purchasing; you have to choose Job No. and Job Task No. in each line on Purchase Order.
This is not currently real example of Job Posting Groups using, but it still has some specifics when you have purchasing for Job. When you post this document, you will get both of posting documents – Purchase Receipt and Purchase Invoice, as well. But when you look in Purchase Receipt, you will see that you have two Item Ledger Entries for each line in document. One of them is Purchase, but second in Negative Adjmt. with the same quantity. It actually means that in the same posting process, system post item purchase (as usually) and item consumption for Job purpose. This posting also creates one Job Ledger Entry for each line in document with Usage Entry Type for each Negative Adjmt. line in ILE.
When you look at G/L Entries, you will see the following result of this posting: