Figured it out after trying random things, turns out the payment gateway I was using was setting orders to ‘on-hold’, so I used that hook and now the core function is firing.
http://www.quickonlinetips.com/archives/2007/11/how-to-create-multiple-dynamic-sidebars-for-wordpress-widgets/
I’m pretty sure some further google searching answered my question. Just had to get the keywords right, I guess.
If there is a better or easier way, someone chime in, by all means!
Ok thanks, that helps a lot, and solves the problem! Appreciated. =D