python – App Engine支持客户端证书

我正在开发一个谷歌应用程序引擎应用程序,我需要使用SOAP连接到Web服务.我正在使用pysimplesoap(使用找到的代码 here修补)来解析xml,并使用客户端证书发出请求.
当我在本地环境的简单单元测试中执行此操作时,它可以正常工作,并且我从Web服务获得了适当的响应.
但是,当我从app引擎中运行完全相同的代码时,我得到了这个：

File "/Users/me/Documents/workspace/blixem/model/communicate/communication_channel.py",line 60,in generate_soap_message_pysimplesoap
    response = client.SendDocument('LA.XML','TESTCASE','data')
  File "/Users/me/Documents/workspace/blixem/lib/pysimplesoap/client.py",line 152,in <lambda>
    return lambda *args,**kwargs: self.wsdl_call(attr,*args,**kwargs)
  File "/Users/me/Documents/workspace/blixem/lib/pysimplesoap/client.py",line 320,in wsdl_call
    response = self.call(method,*params)
  File "/Users/me/Documents/workspace/blixem/lib/pysimplesoap/client.py",line 215,in call
    self.xml_response = self.send(method,self.xml_request)
  File "/Users/me/Documents/workspace/blixem/lib/pysimplesoap/client.py",line 241,in send
    location,"POST",body=xml,headers=headers )
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/httplib2/httplib2/__init__.py",line 1457,in request
    self.disable_ssl_certificate_validation)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/httplib2/httplib2/__init__.py",line 1143,in __init__
    strict,timeout,proxy_info,ca_certs,disable_ssl_certificate_validation)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/httplib2/httplib2/__init__.py",line 1092,in __init__
    raise NotSupportedOnThisPlatform()
NotSupportedOnThisPlatform

我做了一些阅读,发现在urlfetch服务中还没有支持客户端证书.这仍然是这样吗？如果是这样,是否有解决方法？