The Metz 48 AF-1 is indeed a modern flash, offering all P-TTL bells and whistles.
I have it, and its sibling the Metz 58 AF-1 and use them off camera, with an umbrella set on a camera tripod, mostly for family snaps. Some examples :
101051733 photo - phenri photos at pbase.com
101051730 photo - phenri photos at pbase.com
87601438 photo - phenri photos at pbase.com
87285686 photo - phenri photos at pbase.com
This is all with Cactus V2 triggers, which have been consistently reliable for my usage. Naturally, you have to use the flash in manual settings. As there is no connection between camera and flash, any flash offering manual settings can do, you do not need P-TTL units. However P-TTL off-camera is a nice thing to have too, I've used often when in vacation, for example here with the 58 :
96802371 photo - phenri photos at pbase.com
I also on some rare occasions have used the Metz 58 in P-TTL wireless mode with an umbrella, where the controller was the onboard flash. However in my experience there were too many misfires, as there must be a direct line between the onboard flash and the slave unit, and I found using the Cactus V2 wireless triggers much more reliable.