Charging light glowing at idle?

About 5,000 klms ago I noticed my alternator light glowing at idle. I could get it to go out by turning the lights on or by upping the idle speed,  but sometimes I could start it up cold and back the idle right off so it was only just ticking over and it wouldn't come on at all. This had never happened before even at a too slow idle speed, in over 65,000 kms, so I began checking the charging circuit at the battery with a multimeter.
The readings were .... Engine stopped - 12.8 V. At idle - 13.26 V. At 2,000 rpm - 14.05 V, which said to me that the charging system and battery were all in good working order. While talking to a dealer recently, he told me there had been a few voltage reg./rect. failures and mine sounded like one and gave me a part number for a new regulator / rectifier. There is no writing on the regulator to say who makes these, but on the package it came in is written ...... "
Regulator/Rectifier DU-627. Heavy Duty 12V / Single Phase" and lists the models it will fit including Cagivas, Ducatis, Laverdas, and Moto Guzzi 1000 Daytonas, 1000 Quotas, Calis and 1100 Sports. I bought it from a motorcycle shop here in Australia that mainly supplies parts and wrecking. I guess a Ducati shop would be the place to start looking, but apparently it is Japanese made.

Mick Breen