I'm pretty sure it isn't going to work as you want to do it. A single cam needs three pegs to connect the rigging. One for the cable attached to the top limb and two for the string. You have to change both the idler and the cam. I'm not sure why you want to change from the Nitrous cams as they were one of the best systems ever designed, and especially so if you use the X system.
Also, xchanging cam systems often times changes the draw weight range of the bow. Another thing you have to be careful about is the limbs themselves. Depending on just how aggressive the single cam you choose is the limbs might not hold up to the stress. That's one of the reasons Martin changed from laminated limbs for 2011.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver