It seems the difference is that with lathing in a mill, the workpiece is in the spindle and the tooling on the mill table. The Duality is a lathe mounted to the mill table with the workpiece in the Duality spindle and tooling on the mill spindle. Generally, it is easier to mount a workpiece in a lathe or Duality spindle because they are designed for that. Mounting workpieces in a mill spindle usually needs special hardware. It's the same for tooling because a mill is designed to have rotating tools in the spindle, rather than stationary tools on the table. With the Duality, the tool is usually mounted to a fixture clamped to the mill spindle ram, thus bypassing the need to lock the mill spindle to hold a stationary tool. So lathe = wp in spindle, tool on carriage, lathing on mill = wp in spindle, tool on table, Duality = wp in Duality spindle, tool on mill spindle.

Basically, to turn a workpiece on your mill, you need a means to hold and spin the workpiece in your mill spindle. If your workpiece happens to fit into a collet, you should be all set. Then you need a means to hold your tooling on the table. If you have a lathe tool holder on hand you might be able to mill a block that the lathe tool holder can bolt to, then bolt the block to the table. Or, mill a block with a slot and set screws to hold a lathe tool and also bolt to the table.

The g-code should be in lathe form, except Y can be used to set the tool height if needed.