Custom power-up for private and enterprise boards

Currently, there is no way to install custom power-up to the private board, at least I didn’t find such an ability. It makes hard to develop and test power-ups for such boards.
Also, how can I test my power-up for enterprise accounts? I don’t want to buy an enterprise license, but I need to provide some special functions in my power-up for enterprise clients, how can I test it?