Thanks sdetweil2. I was able to successfully stub just the PDF File which is in binary format.
But my requirement is something like this to be more clear
1. SOAP Request A.xml reaches Middleware M
2. Now the Middleware responds back with Aresponse.xml and along with this a PDF File as well comes as attachment (Soap Response that has attachment) looks something like this
-----=_Part_0_15742342.145343243
Content-Type: text/xml; charset=utf-8
Content-Transfer-Encoding: binary
Content-Id: <213456654434543>
<?xml version="1.0" encoding="UTF-8"?><soapenv:Envelope xmlns:
-----
----
--
-
</Aresponse>
</soapenv:Body>
</soapenv:Envelope>
------=_Part_0_15742342.145343243
Content-Type: application/pdf
Content-Transfer-Encoding: binary
Content-Id: <EBF7DF6EAB32B0970B33B96138F6C306>
%PDF-1.4
%????
1 0 obj
<<
/Author
----some binary text here
--
--
-
%%EOF
------=__Part_0_15742342.145343243--