I've done it with charles/fiddler and other proxy checkers.
I've been trying to sniff and send modified requests, spent hours over this.
I know where the problem is but dont know how to solve it atm.
This video is a **** itself as it does not work for the first and does not explain how to do it as a second,don't mess around with ppl buddy.
Probably You're not even author of the video.
As i have written in my previous post, the fact that item is drawn in cauldron and the entry is in your logbook, does not mean that you actually have the items.
I've been waiting for some1 who has experience with that process but been posted by couple of noobs, like "PM me free pls".
I'm still ready to share the way how to do it but only with those who are really ready to go on with this.
Cheers