The indication of the payment to B in the invoice is not prohibited and similarly the indiction of the buyer in the invoice giving the ultimate buyer as C is also not a constraint at all . In fact this was the exact issue covered in 70 STC which I have mentioned in my view.
As for as the endorcement is concerned, it may not be possible to do it if it is a case of door delivery by the seller and the intention of the parties need to be seen.
The type of transaction narrated by you is a 3(b) sale only i.e. E1 sale as long as you do not inerfear in the movement of goods till it is delivered to the ultimate buyer