How to Enable Remove button in "Customer Account Site Business Purpose Tax Details" region on custom

Hi All,

1. Responsibility: Receivables
   Navigation:  Customers > Standard
2. Query the customer.
3. Click on the details link to open up the customer account information.
4. Then you should see all the sites for that customer on that page.
5. Pick any site and click on the details link to open up the customer site information.
6. Click on Payment Details tab. Now on the top right hand side you should see button for 'Tax Profile'. Click on that.
7. On the bottom of this page you should see section with title 'Customer Account Site Business Purpose Tax Details'.
8. Here remove button is Disable.

Please let me know how to enable it. Is there any profile option for this.