Aulani reservations cannot be linked to your MDE. As Keaster said, there really is no reason I suppose. No FP to book, no need for the maps or WDW dining.
I will say I was surprised that when I called ahead to book dining for our recent Vero Beach stay, I later saw that my dining rez's there at Vero were on my MDE account. They had asked for my email.
If you are a DVC Member, simply sign into your online membership account and hit "Dashboard" at the upper right of the home screen. It will show any upcoming reservations you have.
If you're not a member, go to aulani.com and hit, "My Aulani" and it will take you through steps.