Not done this, but from memory you have to heat the internal shift mechanism so that it becomes twistable and slowly twist it until the button is at the front of the shifter.
People then reinforced it with some sort of epoxy resin - I toyed with the idea, but was never brave enough to do it - got a feeling it it brakes your stuffed.
Has anyone considered the newer Audi A6 S-tronic shifters? They have the button on the side and look better than the stock item, I have no idea if they fit tho