Hello Shaneel,
In the blog you used to setup the connection, the last screenshot (transport binding in SOAMANAGER) have you included proxy host, userid and password ?
if yes, you seem to have done all configuration.
I think you need to ask your Sharepoint admin to enable basic authentication for Sharepoint instead of only NTLM based authentication.
https://technet.microsoft.com/en-us/library/gg558567.aspx
Regards,
Siddhesh