Checkbox writeback to Salesforce field

Hello,

I need to implement the following on my document sent for signature :

Add 5 checkboxes (checkbox group with 5 options) on the document (A, B, C, D, E)

The signer should be able to select atleast one of the options (multi-select)

When the document is signed (completed), the checkboxes chosen should fill in a textarea field in Salesforce (or if you suggest any other compatible Salesforce field with DocuSign checkbox field).

The main aim is to writeback the checkbox values in Salesforce.

I have created custom document fields in DocuSign with the writeback option to the text area field. I tried with one checkbox field chosen. The field in Salesforce is filled , but as value 'true' and not the exact value of the checkbox.

Can you please help to implement the writeback of the checkboxes to Salesforce with the exact values?

Thank you in advance for your help.