Due Date of Task

Hi Experts ,

My client  requirement is to create Service Request Doc with Requested Start date as Current & Requested End Date after 3 days of current. I have configured that correctly and it is coming fine. Client wants that through dashboard they can see the status of their Service Request for which i have provided them option of creation of Task doc through Action Profile. But problem is that :

1. In Task doc both Due Date and Start Date are coming as Current. While i want that Due Date should correspond to the Requested end date of service request . For example if i created Service Request doc on 14.6.16 then it is Requested Start date will be same while Requested end date will be 17.6.16. So, when task will create it should show 17.6.16 as due date instead of current date .

2. I have tried lot of  in changes in date profile ,  date rule but could not getting desired result.

Please guide

Thanks