Is there a way to add simple text lines between the trade item lines?

[s1nn3r]

Hey,
Thank you for the effort you put into this library! I am currently trying to achieve an X-invoice export from our ERP system. We use arbitrary texts between the line items, which do not necessarily refer to an article position; sometimes they are headings or general texts. Is there a way to write these into the positions in the X-invoice with line numbers?
When trying to add TradelineItemComments I receive this error on the document validation:
An Invoice that contains an Invoice line (BG-25) where the Invoiced item VAT category code (BT-151) is "Not subject to VAT" shall not contain the Seller VAT identifier (BT-31), the Seller tax representative VAT identifier (BT-63) or the Buyer VAT identifier (BT-48).
Thank you!
Marc

[stephanstapel]

There are multiple elements that can be used for different purposes. So it depends on what you want to achieve.

The validation error you mention is a famous one that has been discussed in multiple places on the internet. Unfortunately this validation doesn't make sense (in this context).