You can edit your profile.
Click to edit your profile, and in the Information section (the section that immediately opens up when you click on the "Profile" button on the ribbon on the top of your screen) you can scroll down until you find a section that says "DN Name *:" with a bar right next to it.
Click on that bar and enter in your DN Name. That means now that whenever anyone here looks on your profile page, they know who you are on DN.
It doesn't matter if your name varies from DA to DN. You're the same person, just with two different account names.
You'll notice here that a lot of the staff have DN Names that vary from their DA Names, so don't worry.