How is the software distributed? .pkg or a drag install app on a .dmg?
I don't have experience with that specific app, but I've had luck in the past creating a separate package that installs the license file (e.g. into /Library/Application Support/AppName/) and then creating a policy that installs the app and the preference file containing the license. If the app asks for the license key on first launch, and then writes this kind of preference file with the key, this approach may work for you. After the policy runs, on first launch the app will see the file with the license and run as expected without prompting the user for the license.
Just a thought.
