I create this XMLPort objet but I want to use data exhange definition , to export a XMl File, I create a schema and 
but It don't create a XML file, and I am not sure how use that , I just want to do a easy example to understand how export xml file using Data echange definition. because after that I will to develop something like a send invoice electronic, Could you help me?
xmlport 50103 DCLSchemaItemsXml
{
Format = Xml;
Direction = Export;
//TextEncoding = UTF8;
UseRequestPage = false;
//TableSeparator = '';//New line
Encoding = UTF8;
schema
{
textelement(Root)
{
tableelement(Integer; Integer)
{
XmlName = 'ItemHeader';
SourceTableView = SORTING(Number) WHERE(Number = CONST(1));
textelement(ItemNoTitle)
{
trigger OnBeforePassVariable()
begin
ItemNoTitle := Item.FieldCaption("No.");
end;
}
textelement(ItemDescTitle)
{
trigger OnBeforePassVariable()
begin
ItemDescTitle := Item.FieldCaption(Description);
end;
}
textelement(ItemTypeTitle)
{
trigger OnBeforePassVariable()
begin
ItemTypeTitle := Item.FieldCaption(Type);
end;
}
}
tableelement(Item; Item)
{
XmlName = 'Item';
RequestFilterFields = "No.";
fieldelement(No; Item."No.")
{
}
fieldelement(Description; Item.Description)
{
}
fieldelement(Type; Item.Type)
{
}
}
}
}
}
