I assume by you saying "negative pulse rear window defogger" that the "pulse" is from pressing the button. If you wire it to a relay to come on with the accessory, it will always come on (as vicrod mentioned), even without you remote starting the vehicle, and even in the summer. You will never be able to turn it off.
I would wire it to a relay that is controlled by the auxiliary function. If the load is less than 200ma, you can wire it straight to the switch. You'll also have to press the auxilary function when you remote start to turn the defogger on, but at least you won't run it all of the time.
Some remotes will pulse the doors locked before starting, but the accessory lead wouldn't be energized at this time to make the defogger work with the locks. I started exploring that as another option, but it won't work.
One final option is if you have a wire off of the alarm that is grounded during remote start. These are usually used to bypass factory security systems, but could be used to run the defogger or relay only during remote starting.