your repeat region should contain a download form whith a hidden element that will get the recordID from the recordset:
<form id="form_<?php echo $row_Recordset['ID']; ?>" name="form_<?php echo $row_Recordset['ID']; ?>" method="post" action="">
<input name="ID" type="hidden" id="ID" value="<?php echo $row_Recordset1['saleID']; ?>" />
<input type="submit" name="button" id="button" value="Submit" />
Then create a new recordset to lookup the file to download. Set this new recordset to filter the ID column on the ID form element.
In the download file behavior, get the file name from the file name column of the new recordset that was created.