How to capture the proxy user id during approval

I (User: SRI) have added Proxy using Global Preference: Manage Proxies: Add Proxy - Added proxy user SRI-PROXY-1

Once I receive a Approval notification

SRI-PROXY-1 login, switch user to SRI

Opens the Approval Notificaiton and Approves

In Post-notification function I need to capture the PROXY User ID for Approval History

How do we capture the Proxy User Id?

I tried wf_context.proxy_user_id -> Its holding the owner id (i.e, SRI)

tried FND_PROFILE.value('PROXY_USER_ID) -> its null

tried storing the notification_id in item attribute and in the following activity tried to get the value from wf_comments based on notification_id, Its not returing any value.