encoding is removed on MSXML2.DOMDocument.loadXML

Hi!
I have an XML string that starts with the following "<?xml version=""1.0"" encoding=""iso-8859-1""?>...

however when loading the string with MSXML2.DOMDocument.loadXML the encoding attribute is removed and all that is left on the first row is "<?xml version="1.0"?>...

I need to set the encoding in order to succeed to send my request to a webservice but I have tried everything without succeeding...

What I have tried for exemple is to: (xmlCustomersRequest beeing my MSXML2.DOMDocument object)
-Call xmlCustomersRequest.childNodes(xmlCustomersRequest.createProcessingInstruction("xml", "version='1.0' encoding='iso-8859-1'")) - this worked BUT it removed the encoding again and only added another <?xml version="1.0"?> at the end of the xml...

-to add the first row upon sending the request: (I remove it first from the xmlstring of course)
objHTTP.Send ("<xml version=""1.0"" encoding=""ISO-8859-1"">" + xmlCustomersRequest.XML) - this wasn't allowed

to replace the "<?xml version=""1.0""?>" upon sending the request:
objHTTP.Send(VBA.Replace(xmlCustomersRequest.XML, "<?xml version=""1.0""?>", "<?xml version=""1.0"" encoding=""ISO-8859-1""?>") - but this wasn't allowed either

If someone have the solution to this problem please please please enlight me!!