Version 2.3.4 of the Waldorf Edition 2, which is now available in your Waldorf account, offers an export feature that allows you to export your kit as an fxp file. This file must be copied to the User/Kit directory of the Attack 3 plugin.

On macOS, you can find it at: User Library/Audio/Presets/Waldorf/Attack 3/Kits

and on Windows at: User/AppData/Roaming/Waldorf/Attack 3/Kits

Then go to the user directory of your Attack 3 and refresh the view using the Refresh function, which you can activate by right-clicking.
Your kit should then appear and be ready to load. The basic sound parameters, such as filters and oscillators, will be applied.