OK, just want to make sure of a couple things I couldn't really tell from your post. It looks like you've got one of the corned beef briskets from the grocery store, right?. It should be in a cryovac pouch and contain a little plastic envelope of pickling spice. If so, then the meat has already been brined in a solution containing pickling spice, cure and a LOT of salt. These are basically made to be boiled, during which process much of the salt will be pulled out. Since you're planning on smoking it, you'll need to soak it for about 6-8 hours changing the water every 45 minutes or so. Otherwise it'll be way too salty. As for not seasoning it, why not just add the pickling spice as a rub before smoking? As JJ said, you're basically turning it into pastrami, so adding the spices to the outside will give you the flavors you're after without additional salt or briining. Just take some coriander seeds, juniper berries and black pepper and mill them to a coarse grind. You won't need any additional salt (I found this out the hard way) and then smoke as you normally would. Depending on whether it's a flat or point would dictate for me whether I'm going to wrap it or not. If it's a point, you can get by with a straight smoke to an IT of 190˚-195˚. A flat might dry out on you, so you may want to foil. I've had good luck with points at 300˚ and smoked for 4 hours, so if you're pressed for time feel free to crank the heat.
So, to sum up:
Soak
Spice rub
Smoke.
It's really as easy as that.
Good luck and let us know how it turns out!
