Someone more knowledgeable than I can chime in with the 'right answer' - but I think you need to replace the voltage regulator with a voltage regulator/rectifier to make your electrical system DC voltage. These are sold by trail tech here in the u.s. -
www.trailtech.net.
Or you can look on ricky stator's website - they sell both an AC voltage regulator (what our bikes come with) and a regulator/rectifier.
www.rickystator.com
If you only want battery power to your speedo/computer, then you might add a small battery pack and use a a diode to isolate it from the rest of the system.
jeff