An Authorization is a standard transaction type for credit cards and is designed to make sure the credit card is valid and funds are available to process a charge when ready (generally within a few days). ACH / e-check (also known as Direct Debit) work with checking accounts and are not designed to process authorizations like credit cards.
In order to work around this you will need to send a Payment Request for $0.01. You would then need your Salesforce developer to create code that will identify and void this transaction after it's been processed.
This will allow you to receive the token and use it for future transactions.