Assign issue to approver and have approver view and approve/deny in customer portal

I want to be able to have an access request or purchase request workflow where the customer creates the request, the service desk assigns the request to an approver and the approver can view the issue in service desk customer portal and action workflow transitions from the customer portal.

currently it seems i have to send approvers to regular jira, when they too should go through customer portal IMO

thanks in advance for any response!