Well VW wasnt the one that Struggled, it was Ricardo.
The Gearbox was by Ricardo, they provide a few F1 teams with their Gearboxes.
Firstly they didnt use anything out of a F1 car, the Tranny was provided by VW, their brilliant Twin-clutch DSG, now the problem with that gearbox is when they gave it to Ricardo, the gearbox could only handle a max of 300HP, why do u think the DSG-equipped Audi TT didnt have more than 250HP.
Ricardo had to make the DSG capable of handling over 1000HP. Had they just used a good-ol-fashioned Stick, they could have easily used a Extrac, Hewlland, zexel or even Ricardos own. But no, VW decided only DSG.
Ricardo used every research they did on their F1 boxes and applied it to the DSG, but it still took them 5 years to perfect.
It had to last over 10years, Had to take much more power than any F1 car, and still cant weight alot.

Its Why I view the Veyron so highly, Its one of the biggest Accomplishments and also one of the biggest Blunders of our time.

anywayz bak on topic :P