A quite common method of sending invoices are sending a pdf-file through e-mail. In addition to this I would like to attach an xml-file. (Here in Finland we use xml-files for electronic invoicing). What would the correct mime-type be for this? My guess is something like:
Content-type: text/finvoice-xml
(finvoice is the name of the xml-format)
I have not been able to find any specifications for this. Any suggestions?