Hi,
I have a Vexta 5phase stepper with 10 wires, and like you was somewhat confused as to how I would hook them up.

Finding a coil is no trouble. With a multimeter measure between one wire, lets say green, and then try the other wires in turn until you find a circuit which of course corresponds
to the coil inside the motor. A few minutes will establish the five separate windings and the wires at each each end.

The next question is how to phase them. What I did was hook a signal generator to one pair, lets say the green wire and it's matching blue wire. Then using an oscilloscope I measured the induced voltage
of the remaining four windings, This allowed to to determine the phase of each coil relative to first one I chose.

The last step is to decide the order in which the phased coils have to be hooked up. This was trial and error....and took about two hours before I found the combination that resulted in the highest
torque and smoothest running by hooking each winding combination in turn to the driver.

Craig