Need Help for invoking Web Services of Income Tax

We are working for India based fin-tech project which need a integration with Indian Income tax department for submitting user income tax filling. We got access to all API, documents and required keys, but we can't run the sample code provided in JAVA. There is a procedure to trigger the call like signing the SOAP request with key file and encrypting the data as per the guidelines. We definitely missing some simple things. We thought of getting experts help here, we prefer some one who is based on Mumbai or Pune, India. We have IP restriction, our IP is registered with IT department and they accept request only from this IP. In case if you are out of Mumbai or Pune , then you need to work in our system through Team viewer. Though this is very simple project, we are ready to pay good price for this Find more details in attached PDF.