The Dons' surprise home defeat to Walsall on the final day of the regular season combined with Huddersfield's 2-0 win over Yeovil saw the Terriers leapfrog the Milton Keynes club to finish fourth in the League One table.
That means they will have home advantage in the deciding game next week.
The Dons finished fifth last season and failed to reach the final, losing 2-0 at Peterborough after beating Posh 3-2 at home in the first leg.
Assistant boss Gorman said: "We will learn from Peterborough.We will go up there and be hard to beat - like we have been all season. We don't mind playing at home or away.
"It doesn't matter where the second leg is - look at Chelsea in Barcelona. It would have been nice to bring them back here but we will go there confident."