I was under the assumption this method would fire after altering data directly through the Dynamics GP application, i was wrong. The only way this method would have been hit would have been through using the methods in the GP Web Services SDK, apparently Microsoft didn't think the back-end of the Dynamics GP software should have this great functionality...
Since this did not fit our requirements i ended up using eConnect's incoming and outgoing services that work together with MSMQ. I can now add the tables i need to monitor via eConnect's Requester Setup Tool. Lastly, i have created a small client service that monitors my custom MSMQ path and instantly obtains the transaction from GP as it happens.
GP development on the web is limited to none (if i did find anything it was irrelevant due to a different version of GP) ... It came down to lots of reading off MSDN to put this together... The GP forums were also no help for this particular case.