How to create a Advance payment on invoice (Peppol network)

Hello,

1/ How to create a Advance payment on invoice for the Peppol network ? https://developer.b2brouter.net/reference/create-invoice

We can specify a type_document but only for FatturaPA (SDI), how can we create Advance payment invoice for a peppol invoice ?

2/ How can we create a Proforma invoice from the API ?

Many thanks,
Alexandre