Sorry for the delay.
The easiest method of data entry regarding a unique partition tag is to leave your Accounts Payable screen as it is showing the Separate columns for Financial and Job Cost (JC) and enter the Job Costing entries through the Job Costing Journal. We had created a Bookmark for this.
It is possible to enter both through the same AP ledger but you will need to select View > Sorted By > Select Index and blank the Begin Tag and End Tag fields and get used to viewing Accounts Payable ledgers showing all tags (Financial, JC, Order, Budget, etc) which could become confusing. You can then always change the select Index back to Financial to suit your needs.
I would stick with entering the Job Costing entries within he Job Costing journal as it is easier.
I hope this helps.
Regards to all,