How to declare schemas and encoding on XMLport?

Hi,

Hopefully someone who have experience with XML could instructs to me in the right direction.
I'm struggling with NAV2016, XMLports and XML syntax.

My goal is to create XMLport for e-invoicing.
Whole XMLport structure is possible to create with existing tools, but troubles come with schemas and encoding.

At the beginning of file should start with exact syntax:
<?xml version="1.0" encoding="ISO-8859-15"?>
<Finvoice Version="2.01" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance&quot; xsi:noNamespaceSchemaLocation="Finvoice2.01.xsd">

First miss: Nearest NAV encoding is ISO-8859-2, so how to change this to ISO-8859-15?

Second miss: How declare Schema instance and Schema Location with shown syntax?
So far my best shot is <Finvoice xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance&quot; Version="2.01" noNamespaceSchemaLocation="Finvoice2.01.xsd">
But this is not enough.

BR,
Derek