Once you have created a custom drum kit or modified a preset kit you will want to select "Save Kit" at the bottom of the window to save your kit as a preset.
Once your kit has been named it will show up in your User.lib folder. This can be found within the SSD Sampler under the "Kits" menu.
You may have to select the "refresh" button to view your new preset.
If your drum kit has involved custom midi mapping you will need to save the conversion.
If you have any issues please submit a request to speak with a support agent.