Supplier Payment v Bank Payment

Hi,
I am trying to understand the correct posting type to make on Front Accounting. We came from using Sage 50, which basically had 2 options, Pay Purchase invoices or Pay Expenses. The system works great for supplier invoices where you have inventory and then pay the supplier. The issue seems to be with 'Expense' payments. If we just put these down as a Supplier Payment the amount come allocated to the Accounts Payable, making this incorrect, the correct expense nominal account isn't posted and the supplier balance goes into a minus. It would appear we would need to first post an invoice and then a payment to make this work correctly. If we post these payments under Bank and General Ledger as a Bank Payment and select a supplier payment (to log onto the correct supplier account) then although the correct expense nominal account is posted the Supplier account shows a minus. Should the system create an expense invoice on the supplier account to counter act the payment to bring the balance to zero?
We have spent a year incorrectly posting expense invoices and need to rectify these. More importantly we need to make sure we post these correctly going forward.
Any help you can provide would be very helpful.
Thanks,
Steve