diff --git a/src/BeSimple/SoapClient/SoapClient.php b/src/BeSimple/SoapClient/SoapClient.php
index c5b9117..d264090 100644
--- a/src/BeSimple/SoapClient/SoapClient.php
+++ b/src/BeSimple/SoapClient/SoapClient.php
@@ -277,6 +277,8 @@ class SoapClient extends \SoapClient
                 $converter = new SwaTypeConverter();
                 $converter->setKernel($this->soapKernel);
             } elseif (Helper::ATTACHMENTS_TYPE_MTOM === $options['attachment_type']) {
+                $xmlMimeFilter = new XmlMimeFilter($options['attachment_type']);
+                $this->soapKernel->registerFilter($xmlMimeFilter);
                 $converter = new MtomTypeConverter();
                 $converter->setKernel($this->soapKernel);
             }
diff --git a/src/BeSimple/SoapClient/XmlMimeFilter.php b/src/BeSimple/SoapClient/XmlMimeFilter.php
new file mode 100644
index 0000000..142a271
--- /dev/null
+++ b/src/BeSimple/SoapClient/XmlMimeFilter.php
@@ -0,0 +1,75 @@
+<?php
+
+/*
+ * This file is part of the BeSimpleSoapClient.
+ *
+ * (c) Christian Kerl <christian-kerl@web.de>
+ * (c) Francis Besset <francis.besset@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace BeSimple\SoapClient;
+
+use BeSimple\SoapCommon\FilterHelper;
+use BeSimple\SoapCommon\Helper;
+use BeSimple\SoapCommon\Mime\MultiPart as MimeMultiPart;
+use BeSimple\SoapCommon\Mime\Parser as MimeParser;
+use BeSimple\SoapCommon\Mime\Part as MimePart;
+use BeSimple\SoapCommon\SoapRequest;
+use BeSimple\SoapCommon\SoapRequestFilter;
+use BeSimple\SoapCommon\SoapResponse;
+use BeSimple\SoapCommon\SoapResponseFilter;
+
+/**
+ * XML MIME filter that fixes the namespace of xmime:contentType attribute.
+ *
+ * @author Andreas Schamberger <mail@andreass.net>
+ */
+class XmlMimeFilter implements SoapRequestFilter
+{
+    /**
+     * Reset all properties to default values.
+     */
+    public function resetFilter()
+    {
+    }
+
+    /**
+     * Modify the given request XML.
+     *
+     * @param \BeSimple\SoapCommon\SoapRequest $request SOAP request
+     *
+     * @return void
+     */
+    public function filterRequest(SoapRequest $request)
+    {
+        // get \DOMDocument from SOAP request
+        $dom = $request->getContentDocument();
+
+        // create FilterHelper
+        $filterHelper = new FilterHelper($dom);
+
+        // add the neccessary namespaces
+        $filterHelper->addNamespace(Helper::PFX_XMLMIME, Helper::NS_XMLMIME);
+
+        // get xsd:base64binary elements
+        $xpath = new \DOMXPath($dom);
+        $xpath->registerNamespace('XOP', Helper::NS_XOP);
+        $query = '//XOP:Include/..';
+        $nodes = $xpath->query($query);
+
+        // exchange attributes
+        if ($nodes->length > 0) {
+            foreach ($nodes as $node) {
+                if ($node->hasAttribute('contentType')) {
+                    $contentType = $node->getAttribute('contentType');
+                    $node->removeAttribute('contentType');
+                    $filterHelper->setAttribute($node, Helper::NS_XMLMIME, 'contentType', $contentType);
+                }
+            }
+        }
+
+    }
+}
\ No newline at end of file
diff --git a/tests/AxisInterop/MTOM.php b/tests/AxisInterop/MTOM.php
index 8f091bc..08d8723 100644
--- a/tests/AxisInterop/MTOM.php
+++ b/tests/AxisInterop/MTOM.php
@@ -21,12 +21,32 @@ class AttachmentRequest extends AttachmentType
 {
 }
 
+class base64Binary
+{
+    public $_;
+    public $contentType;
+}
+
+class AttachmentType
+{
+    public $fileName;
+    public $binaryData;
+}
+
+class AttachmentRequest extends AttachmentType
+{
+}
+
 $options = array(
     'soap_version'    => SOAP_1_1,
     'features'        => SOAP_SINGLE_ELEMENT_ARRAYS, // make sure that result is array for size=1
     'trace'           => true, // enables use of the methods  SoapClient->__getLastRequest,  SoapClient->__getLastRequestHeaders,  SoapClient->__getLastResponse and  SoapClient->__getLastResponseHeaders
     'attachment_type' => BeSimpleSoapHelper::ATTACHMENTS_TYPE_MTOM,
     'cache_wsdl'      => WSDL_CACHE_NONE,
+    'classmap'        => array(
+        'base64Binary'      => 'base64Binary',
+        'AttachmentRequest' => 'AttachmentRequest',
+    ),
 );
 
 /*
@@ -42,10 +62,13 @@ $sc = new BeSimpleSoapClient('MTOM.wsdl', $options);
 //var_dump($sc->__getTypes());
 
 try {
+    $b64 = new base64Binary();
+    $b64->_ = 'This is a test. :)';
+    $b64->contentType = 'text/plain';
 
-    $attachment = new stdClass();
+    $attachment = new AttachmentRequest();
     $attachment->fileName = 'test123.txt';
-    $attachment->binaryData = 'This is a test.';
+    $attachment->binaryData = $b64;
 
     var_dump($sc->attachment($attachment));
 
diff --git a/tests/AxisInterop/MTOM.wsdl b/tests/AxisInterop/MTOM.wsdl
index 178ee35..f0c9a6d 100644
--- a/tests/AxisInterop/MTOM.wsdl
+++ b/tests/AxisInterop/MTOM.wsdl
@@ -80,10 +80,10 @@
   </binding>
   <service name="MTOMSample">
     <port name="MTOMSampleSOAP12port_http" binding="tns:MTOMServiceSOAP12Binding">
-      <soap12:address location="http://192.168.0.104:8080/axis2/services/MTOMSample.MTOMSampleSOAP12port_http/"/>
+      <soap12:address location="http://localhost:8080/axis2/services/MTOMSample.MTOMSampleSOAP12port_http/"/>
     </port>
     <port name="MTOMSampleSOAP11port_http" binding="tns:MTOMServiceSOAP11Binding">
-      <soap:address location="http://192.168.0.104:8080/axis2/services/MTOMSample.MTOMSampleSOAP11port_http/"/>
+      <soap:address location="http://localhost:8080/axis2/services/MTOMSample.MTOMSampleSOAP11port_http/"/>
     </port>
   </service>
 </definitions>