Curious if you ever came up with a solution?

I came across the following which I will perhaps try with Wells Fargo:

Implementation Details of the U.S. ACH Plug-In

In Acumatica ERP, instead of using the predefined export scenarios, you can use the flexible U.S. ACH plug-in, which can be adjusted to meet customers’ and banks’ requirements.

The plug-in is more user-friendly and easier to configure than the predefined export scenarios are. The plug-in provides the flexibility to adjust ACH export settings according to known variations in customers’ and banks’ requirements for exported US ACH files. This flexibility includes the following capabilities:

• An offset record can be added to an ACH file.
• Addenda records can be added to an ACH file, and rules can be configured to generate the addenda description.
• The mapping of ACH fields can be changed. For example, the Company Identification remittance detail can be configured to be exported to the Immediate Origin field of the ACH file.
• The format of the File ID Modifier field of the ACH file can be adjusted (that is, it can be set to either 0-9, A-Z or A-Z, 0-9).
• The value in the Service Class Code field of the ACH file can be set to 200 (mixed debits and credits) or 220 (credits only). Also, the value in the Standard Entry Class Code field can be set to CCD (Corporate Credit or Debit) or PPD (Prearranged Payment or Deposit).
• The type of a vendor’s account (savings or checking) can be specified. The system considers this type when it generates the transaction code for records of type 6 in the ACH file.

The use of the ACH plug-in provides enhanced validations, including control of the ACH export settings and verification of data validity.

Setup of Payment Processing by Using the U.S. ACH Plug-In

To start paying your vendors by using the U.S. ACH plug-in, you should perform the following steps:

1. You sign up for the ACH service with the ACH operator. As part of the sign-up process, you receive the credentials with which your company is registered in the ACH network, such as the account number, bank routing number, and company identification.
2. You set up agreements with your vendors covering ACH transaction authorization, and you get information about their accounts in the ACH network.
3. You set up the payment method to be used for ACH payments. For details, see To Add a Payment Method for the U.S. ACH Plug-In.
4. You specify remittance information (ACH credentials) for each cash account that you are going to use as a source for paying your vendors. For details, see To Add Remittance Information to a Cash Account.
5. You assign the payment method intended for ACH payments to each vendor that will accept ACH payments. By using the ACH-related information that you collected from each vendor in Step 2, you fill in the settings of the payment method on the Payment tab of the Vendors (AP303000) form. For details, see To Add a Payment Method for the U.S. ACH Plug-In.