How to trigger a custom webservice from C4C to ECC

Hi,

I want to add a button in Sales Quote and when clicking it, it has to trigger a webservice to ECC, pull the data from ECC and put in a field in sales quote.

I have found an are where i can add a button and now the question is how i can trigger a webservice from C4C using Development studio.

P.S. HCI is used for the integration and I am new to cloud development.

Thanks and Regards,

Ajith Jesuwaram