Hi Steve,

There is good news and bad news. The good news is that yes, the Det-Document number field is used to specify the invoice number to which you want to specifically apply payment when importing either a Payment or a Prepayment transaction.

Within the help file, there is a page that lists all of the template format requirements for importing manual check batches, but admittedly I had to locate it through the Topic Search process rather than a direct link from the Importing / Exporting page. When I searched for 'import manual checks', the second topic listed with the title 'Import Format Notes - Checks' is the one you want.

The bad news is that although there is also another field in the import manual checks template called 'Det-Document Type' to allow applying payment amount to other transaction types such as credit notes or debit notes, that area currently isn't working. Only invoices can currently be applied to when importing manual check payments.

Hope all of this information helps.