API DocuSign with SugarCRM

As a company we create contracts with the help of DocMerge (SugarCRM) and send it digitally to our customers via DocuSign. DocuSign provides our customers to have a look into the contract and gives the opportunity to complete the contract in order to fill in required fields on the contract. However, the fields that are placed in the contract are empty fields and needs to be completed by the customer while this information is already known within SugarCRM. Therefore, we would like to merge this field with the data that is known from our SugarCRM database. On the picture below I have visually shown how our contracts look like at this moment (on the left) and what we would like to achieve with developing the integration between DocuSign and SugarCRM (on the right) which makes the work more easy for both our sales colleagues as also our customers to fill in in the form digitally. Is there any company that use the integration of DocuSign together with SugarCRM and would like to expand it? Or is there any company that use the integration with DocuSign but already developed it by themselves?