The answer depends on which accounting process you are using.
Cash Accounting method:
- You need to split raise separate expenses; one expense for the amount that has been paid, one expense for the amount that has not yet been paid
- For the amount that has been paid, create the expense by categorising the bank transaction
- For the amount that has not yet been paid, create the expense from the Expenses screen
- Expenses should be raised in the normal way
Accrual Accounting method:
- Raise an expense in the normal way