New line in text constant using STRSUBSTNO

Hi all,

I'm trying to add aditional information to a sales invoice when using "get shipment lines".
The first line is always the "shipment no" and is found in table 111: SalesLine.Description := STRSUBSTNO(Text000,"Document No.");
I would like to add a second line with the customer reference and external doc no.

SalesLine.Description := STRSUBSTNO(Text000,"Document No.","Customer Order Reference","External Document No.")

I tried all possible solutions to insert a new line, but none seem to work in this case. And almost all hits on google refer to RDLC...

Can someone point me in the right direction please?