When using a Single AR Summary Account, the credit side of the payment will automatically pull from the AR Summary account defined in Configuration Default Accounts.  If the system is set up to use Multiple AR Summary Accounts, the credit side of a payment can be edited on the payment GL Distribution tab. This would allow each payment to post to a specified account.

For more information, refer to How to define multiple AR Summary Accounts (BB273920)

There is a workaround using Application Restrictions that may work as well, if you need the Payments to apply towards Advance Deposits:

1.  Create an Advance Deposit Billing Item with the GL Account you want to use (different from Default Account)
2.  Create an Application Restriction with only the Item from Step 1 selected to Apply to
3.  Add the Advance Deposit to the Records needing it
4.  Create a new Deposit and on the Defaults tab, add the Restriction from Step 2 to use
5.  Import the Payments with the following fields: Record ID, Deposit ID, Payment Date, Payment Amount, and Payment Method
6.  The Payment applies to the Advance Deposit it's restricted to, and reflects the correct GL Account punched in for Step 1 (different from the Default Account)