Just make sure your in play bet is at odds over evens as it need to cover your loss on pre game bet.. typical odds on this usually (in decimal) 1.16 DC WIN and 3.60 DRAW.
So make sure your draw is your in play NOT pre game bet.
Obviously other ways to do it if you don't think draw will come...
done it everytime this offer been on. a win fetches between £13-20 clear profit and a draw fetches between £70-120 clear profit.. had a few draws too. small print says ya cannot cover ya bets like this but they paid out the previous times I done it (around 10 times)
always do same thing with these myself.. double chance home/away win pre game (usually fetches around £15 profit). Then draw inplay (usually fetches around £80-£100 clear profit).