Luggage storage in Capri

One of the Capri tourism websites notes a left luggage facility at a souvenir shop at Marina Grande.
http://www.capri.net/en/capri-faq

"Does Capri have a luggage deposit?
The island's luggage deposit is located in a souvenir shop, directly opposite the docks in Marina Grande. Before leaving your bags, make sure to check the opening and closing times."

Checking the closing time of the left luggage facility, before you leave it, is especially important--otherwise you don't get your luggage back until the next day.

Would it be possible to check your luggage in the place you are departing from? if you have to pass through Napoli by train, for example, you could check your bags at the station and pick them up later, or leave them at your hotel if you are staying in Sorrento (sounds like Capri is a daytrip?).

Thank you for the suggestions.