UPDATE: Simon Fell caught me in the midst of evil, as he rightfully points out that when one bypasses a SOAP Stack and "does their own thing" as I have here, I must perform the SOAP Processing Rules.  I've update the code below, changes in RED. 

NOTE: In the interest of correctness, I've included namespace qualification in the NEW code.

A fellow emailed me wanting to get a PDF file out of a SOAP Envelope and write it directly out to the browser using Classic ASP.  Here's the code I used:

<%
Set m_Doc = Server.CreateObject("MSXML2.DOMDocument.4.0")
m_Doc.async = false
m_Doc.ValidateOnParse = false
'This could come from whereever, ADO, a file, another Web Service.
m_Doc.Load Server.MapPath(".") + "\\soapresponse.txt" 
m_Doc.setProperty "SelectionNamespaces", "xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' xmlns:def='http://localhost/'"

'There's nothing that I DO understand, so if there's anything I must, I'm screwed.
Set oHeader = m_Doc.selectNodes("//soap:Envelope/soap:Header/*[@soap:mustUnderstand = '1']")
If (Not oHeader Is Nothing) Then
   If (oHeader.Length > 0) Then
      Response.Write("Crap! I can't continue! What to do?")
      Response.End
   End If
End If

'Yes, it's a // XPath, but that's the LEAST of our problems before we get into microperf
Set oNode = m_Doc.selectSingleNode("//def:GetImageAsBase64Result")
'This is the Magic that makes it possible.  Otherwise you'll get a string.
oNode.dataType = "bin.base64"
Response.ContentType="application/pdf"
Response.AddHeader "Content-Disposition", "filename=whatever.pdf"
Response.BinaryWrite oNode.nodeTypedValue
%>

This is given a SOAP Response like this:

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<GetImageAsBase64Response xmlns="http://localhost/">
<GetImageAsBase64Result>JVBERi0xLjI SNIP....etc...