[TYPO3-shop] hook during order processing

[Vikram Mandal]

Hi,

I need to call a function when an order is placed.. the basket content 
should also be available to my function. I came across this code in the 
class.tx_ttproducts_finalize_div.php:

             // This cObject may be used to call a function which clears 
settings in an external order system.
             // The output is NOT included anywhere
         $pibase->getExternalCObject('externalFinalizing');


Can someone please guide me if this is the correct function and how do I 
use it?

And pointer to docs will also be very helpful.

Regards,
Vikram Mandal