Probably not. Although a 4.8V battery will work, 600 mAh is too small. Saito recommends at least a 6V battery and at least 1000 mAh. Specifically:
"The Saito ignition has an operating voltage from4.8–9.0 volts. Saito recommends the use of a 5-cellNi-Cd/Ni-MH battery or a 2-cell Li-Po/Li-Ion/Li-Fe with
a minimum of 1000mAh. The recommended battery isthe Team Orion® Avionics Li-Fe Receiver Pack 1300mAh6.6V (ORI60503). "
You could also use a Tech-Aero BEC and just use your receiver battery to power the ignition. I would probably up the mAh a bit though, say 2500-3000 mAh.