Sat 05 May 2004United's future is put on the lineManchester Utd v Millwall: Millwall have travelled to Cardiff on the back roads. They are the first side in 51 years to sneak through to the FA Cup final without meeting a team from the top division. Today the tournament gets its own back by putting them in the path of a juggernaut.The television commentators will not run short of picturesque incongruities when, for instance, Marvin Elliott, who was an apprentice at The Den a year ago, has to tackle Ryan Giggs, appearing in his fifth final.