While repositioning an aircraft at DAB at dusk; the pilot ran off the paved surface and into a ditch causing a prop strike and engine stoppage.

Narrative

I was repositioning the aircraft from the Southeast ramp at Daytona Beach International Airport. I was initially instructed by the ground controller to taxi to the ramp via Echo and hold short of runway 7 Right. I read this back to the controller; and taxied to the hold short line for 7 Right. There was a landing aircraft; so I turned off my taxi light as a courtesy for the other pilot. I was then told to cross runway 7 Right and taxi to the ramp via Echo. After crossing 7 Right and after passing taxiway Sierra; I noticed a cluster of blue taxiway lights that appeared to be the entrance to the ramp. I still had my taxi light off; and upon approaching what I thought was the ramp entrance; I noticed a big patch of downward sloping grass. I immediately stepped on the brakes; but I had already rolled onto the downward sloping patch of grass; and the momentum was too great to bring the aircraft to a complete stop to prevent it from rolling into a small ditch. The propeller struck the grass; and then the engine died. I got out of the airplane and went to get assistance.