Move Article Thread at Publish Time

[Cadellin]

Background:
On our site we publish news articles on a regular schedule using the CMS promote tool so the comments on the forum and CMS are shared. Unfortunately this means we have to be around to move the thread into a news forum from a private forum just before each article is published - I want to automate that process of moving the associated thread.

What I'm trying to do:
I'm trying to create a plugin which will automatically move a promoted thread to a certain forum when the article it's associated with is published at whatever time it's set to appear.

So far though I'm unable to find any hook which is called at the time a scheduled article is published.

Can anyone offer me any hints/tips as to where I should start looking? Is this even possible?

Thanks