Yes it's part of the assembly.
Those two systems are as different as night and day. The 1100di pump provides just enough psi (25) to keep the injectors full. The injectors acutally produce thier own pressure which is why they require the 45 volts.
There are folks selling just the pump for the 15f. Just google it. They're about 60 bucks. I would also make sure to get a new filter and make sure the pump comes with a new sock. While you have the pump out make sure the tank is clean, and keep the tank more than 1/4 full to keep from starving the pump.
The fuel actually cools and lubes the pump.