Hooking into order creation process

[simonlogan]

I have a client who needs a customised CSV file created for each order placed and I have the basic scripting written which does this, I now need to hook this into the VM order creation process so that it will trigger the code to fire at the time an order is created and also so that it can retrieve the various values required for that order.

Can anyone tell me which file(s) I should be looking at to do this?

[PRO]

the payment plugin

or the shipping plugin

[simonlogan]

Thanks.