from the amp's effect loop out into the line level in on the back of the pod xt pro, then from the 1/4" analog model out of the pod xt pro into the amp's effects return. On the Pod, set up some channels with the effects you want but set the amp sim to none (off) and turn off a.i.r (cab emulation). and then set one channel as total clean (i.e. - no effects, amps or air). Ifyou have a pedal, you can use it like stomp boxes.

And that should do it! 

hip63