Need help tracking registration/display name creation with Google analytics

I was curious if anyone is tracking community registration with Google Analytics, and what mechanism you're using to know that a user completed the process (aka created a display name).

In our soon to launch set up, we're leveraging SSO with our main site. We're planning on launching an email campaign to urge existing customers (IE already have a user account for our site) to engage with our community.

We're looking at the creation of a display name as a conversion goal for this campaign.

Based on the basic set up (with SSO), the page flow looks like this:

Land on Community -> click post/respond/kudos/sign in > activates SSO login page > Create a Display Name/agree to T&C

By default, once you create the display name, you're taken back to the page you came from or the community landing page where you see a success interstitial - there is no distinct landing page. I was hoping to find a distinct confirmation to easily plug into GA w/o any IT intervention, but that doesn't seem to exist.

Any recommendations are appreciated!