BPM- Send FYI notification to Invoice Requester after Invoice approval

Summary:

BPM- Send FYI notification to Invoice Requester after Invoice approval

Content (required):

Need to send FYI notification to both Invoice requester and a named list of users under the group after invoice approval using BPM Task.

I have created a separate participant at last stage of the process (sequential -> FYI). This is a Rule based participant using List Builder.

Now to conditionally restrict this rule to be sent only after approval, I tried using different conditions available as part of Payload but they are not working. Please let know any pointers to achieve this requirement.

e.g.

Invoice Header.Workflow Approval Status