[rt-users] "On Approval" notifications - how to set?

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I have created a queue "Purchase" and a queue "Purchase-Approval". 

In "Purchase", I create a template and a scrip, that create an approval ticket in "Purchase-Approval". Works OK: when a ticket is submitted to  "Purchase", an approval ticket is automatically created in "Purchase-Approval". Although it is not listed in "Purchase-Approval", the dependency is created and visible in the "Links" section of the parent ticket.

How and where do I create a template/scrip pair(s) to notify the parent ticket Owner and/or Requestor that their request has been approved? My assumption was that I have to create them in "Purchase-Approval" as an action triggered on resolve, but that doesn't seem to work. 

I'd like to note that I will need several approval queues. I have read the 'official' wiki-based documentation, including http://requesttracker.wikia.com/wiki/ManualApprovals. I do not get it about __Approvals queue. Can there be only one single queue for approvals?

Thanks in advance.

A.