How to replace a drive belt on a John Deere LX 255?

I have a John Deere LX255 Mower with broken belt. I have purchased an 88" belt which I believe is the correct length. I have it over the transmission pulley, through the idler pulleys and around the steering drive. I am having difficulty getting it past the mower drive pulley, the mower deck clutch and onto the drive pulley. Does the deck drive pulley and clutch have to come off?