Declaration missing http://www.w3.org/XML/1998/namespace

Question

I have a xslt1.0 mapping file that looks like this at the top:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:s0="http://F.FlatFileSchema1" xmlns:xml="http://www.w3.org/XML/1998/namespace" exclude-result-prefixes="s0">
    <xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
    <xsl:key name="groupbyproduct" match="Products" use="product"/>
    <xsl:template match="/s0:Product">
        <enfinity xsi:schemaLocation="http://www.intershop.com/xml/ns/enfinity/7.1/xcs/impex catalog.xsd http://www.intershop.com/xml/ns/enfinity/6.5/core/impex-dt dt.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.intershop.com/xml/ns/enfinity/7.1/xcs/impex" xmlns:xml="http://www.w3.org/XML/1998/namespace" xmlns:dt="http://www.intershop.com/xml/ns/enfinity/6.5/core/impex-dt" major="6" minor="1" family="enfinity" branch="enterprise" build="build">

When I use BizTalk in Visual Studio to create an xml file from a csv, the declaration at the top looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<enfinity xsi:schemaLocation="http://www.intershop.com/xml/ns/enfinity/7.1/xcs/impex catalog.xsd http://www.intershop.com/xml/ns/enfinity/6.5/core/impex-dt dt.xsd" major="6" minor="1" family="enfinity" branch="enterprise" build="build" xmlns="http://www.intershop.com/xml/ns/enfinity/7.1/xcs/impex" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dt="http://www.intershop.com/xml/ns/enfinity/6.5/core/impex-dt">

I don't think the order matters particuarly, but it is definitely missing this line within <enfinity

xmlns:xml="http://www.w3.org/XML/1998/namespace"

How do I ensure this is included please?