diff --git a/lib/savon/header.rb b/lib/savon/header.rb
index a8a41361..b41d8a31 100644
--- a/lib/savon/header.rb
+++ b/lib/savon/header.rb
@@ -61,12 +61,7 @@ def build_wsa_header
        convert_to_xml({
          'wsa:Action' => @locals[:soap_action],
          'wsa:To' => @globals[:endpoint],
-         'wsa:MessageID' => "urn:uuid:#{SecureRandom.uuid}",
-         attributes!: {
-          'wsa:MessageID' => {
-            "xmlns:wsa" => "http://schemas.xmlsoap.org/ws/2004/08/addressing"
-          }
-         }
+         'wsa:MessageID' => "urn:uuid:#{SecureRandom.uuid}"
        })
     end
 
diff --git a/lib/savon/operation.rb b/lib/savon/operation.rb
index 9489d60e..2328aa51 100644
--- a/lib/savon/operation.rb
+++ b/lib/savon/operation.rb
@@ -9,6 +9,11 @@
 module Savon
   class Operation
 
+    SOAP_REQUEST_TYPE = {
+      1 => "text/xml",
+      2 => "application/soap+xml"
+    }
+
     def self.create(operation_name, wsdl, globals)
       if wsdl.document?
         ensure_name_is_symbol! operation_name
@@ -107,6 +112,15 @@ def build_request(builder)
       request.url = endpoint
       request.body = builder.to_s
 
+      if builder.multipart
+        request.gzip
+        request.headers["Content-Type"] = ["multipart/related",
+                                           "type=\"#{SOAP_REQUEST_TYPE[@globals[:soap_version]]}\"",
+                                           "start=\"#{builder.multipart[:start]}\"",
+                                           "boundary=\"#{builder.multipart[:multipart_boundary]}\""].join("; ")
+        request.headers["MIME-Version"] = "1.0"
+      end
+
       # TODO: could HTTPI do this automatically in case the header
       #       was not specified manually? [dh, 2013-01-04]
       request.headers["Content-Length"] = request.body.bytesize.to_s
diff --git a/spec/savon/message_spec.rb b/spec/savon/message_spec.rb
index 24c56a7f..1c6d360f 100644
--- a/spec/savon/message_spec.rb
+++ b/spec/savon/message_spec.rb
@@ -55,16 +55,6 @@
         end
       end
     end
-
-    context 'wsa:MessageID' do
-      let(:message_id_tag) {
-        '<wsa:MessageID xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/08/addressing">'
-      }
-      it 'should include xmlns:wsa attribute' do
-        response = client.call(:something, message: {})
-        expect(response.xml).to include(message_id_tag)
-      end
-    end
   end
 
 end