You are trying to add the Attachment tab (folder) available in Sales Quote, Sales Order in your Form Template but the information comes blank, however it works for the Purchase Order Template, for example.
SAP Business ByDesign
For CRM documents this functionality is current not available.
You can consult the following KBA on how to proceed: 2531827 - Functionality Currently not Available
Attachment ; Form ; Template ; Sales Quote ; Sales Order ; CRM , KBA , AP-CQP-CQ , Customer Quote , AP-SLO-SO , Sales Order , How To