When I built my new espresso bar, I decided that it was time to plumb in my slightly modified Giotto.
I looked at an espresso plumbing kit, but wasn't convinced that I needed a $100 kit with a $50 water solenoid before the pump inlet. The solenoid in the kit is high quality - the same one that's behind the 9 bar pump in my machine. At the houe water line, I see all of 30 psi(about 2 bar) or so, making it a bit over-spec'd. After some thought, I wondered if I could use the same water solenoid that's used on a refridgerator.
I picked up one off ebay for about $12 plus shipping, and let it sit on my desk until I was ready. Today, it's worked flawlessly for several months, so I think I can declare it a success.

Water feeds from the inlet valve (yes it's cold on the left.) to the solenoid. From there, it feeds the pump, the pump feeds the machine.
The solenoid keeps normal water pressure from making the espresso machine constantly leak. Without it, the machine will drip continally. If you don't have a drain on your drip tray, it will lead to disaster.
To simplify wiring, I mounted a junction box in my cabinet and ran armored wire to my pump. Inside the box, the solenoid is wired to the same relay operated circuit as the pump. Any time the pump turns on, the solenoid is activated.
All the hoses feed to the next cabinet, where they pass up to the espresso machine. The drain line is connected to a simple drain that I added to my drip tray with some slightly modded brass fittings.
The solenoid is the blue and red fixture in the picture. Searching for 'GE solenoid' should turn up a similar item on ebay. (Most appliance shops will have them in stock too.)
The solenoid accepts 1/4" npt input, and has two ouputs. It accepts 120v, so it's just a matter of wiring it in parallel with the pump. The ice maker side is rated for more intermittent use to keep costs down, so don't use it to supply the machine - it will probably burn out if over-used.
The water dispenser side has a better solenoid, but requires a bit of adaptation to work. I added a length of 5/16" poly hose from the dispenser side to a 5/16" to 1/4" compression adapter. The 1/4" line connects the adapter to a guest type fitting (push in) on the pump.
My original how-to on adding an external pump to the giotto is here.