I've made many a pastrami with store bought corned beef. Those things are tough to rid of the salt.....luckily for me nobody who's tried my pastrami has ever mentioned that it was too salty. I quit trying to soak the salt out of them after a few times noticing little difference in the finished product.
One of the ingredients that I use that you didn't list is juniper berries. The piney taste they add really offsets the saltiness. You might want to give them a shot.....World Market carries them if you have those in your area. If not you can do as I do and order in bulk from one of the online spice web sites. Penzeys has great prices and their selection is second to none.
I'll give you the very simple rub recipe that I use.....course ground black pepper, ground coriander and crushed juniper berries are the only spices that I use. Rub down the corned beef a few nights before and vacuum seal (or tightly wrap) it and let it sit in the fridge. I've even frozen them ready to smoke and they turn out great.
P.S. That pastrami looks awful lonely in that big ol' smoker all by itself! If you looking for other things to smoke that don't break the bank try throwing some onions, potatoes or even apples on there. They make for very tasty treats.