I use version 26.1. If I run the action "Send..." on page "Posted Sales Invoice" and set the value "Electronic Document" in the field "Email Attachment" and the value "XRECHNUNG" (Codeunit "Export XRechnung Document") in the field "Format", an XRechnung file (XML) is generated as an attachment. The validators (e.g. "https://app.b2brouter.net/en/validation", "https://erechnungsvalidator.service-bw.de") report that the file is invalid because of a failed rule:
[BR-DE-15] The "Buyer reference" (BT-10) element must be submitted.
How can I set the buyer reference for XRechnung files sent by e-mail?
(I have already set "Your Reference" in the field "Buyer Reference" for the e-document service with the document format "XRechnung". The field "Your Reference" of the posted sales invoice has a value.)