Subreports in FboOne are loaded upon runtime, by replacing the textboxes with the particular naming convention with real subreport templates saved into the FboOne template documents section.
The section displaying the receipt subtotal and VATs makes no exception
Testing and verifying
In order to be able to test the subreport within the Report Builder the parameters visibility needs to be changed (by default this is set to "Hidden" so that no additional parameters are displayed in case the report is viewed in the report viewer, ex: in the report page when generating a report)
Afterwards values can be added to each parameter in order to view the result
Create custom receipt layouts using RDL
Download: sample invoice RDL template from here: ReceiptVatSubtotalSubreport.rdl