Wow! 6 years and you still haven't reported back. Would be nice if you did. I'd love to see the schematic because my WES51 is currently doing the exact same thing. From your description, it appears that the WES51 works just like the WD1.I will look at it and report back later.
Here's a list of the chips that are on my circuit board.
PRECISION CMOS SINGLE MICROPOWER OPERATIONAL AMPLIFIER
LM78Lxx 100-mA Fixed Output Linear Regulator
8-Pin, 8-Bit CMOS Microcon troller with A/D Converter and EEPROM Data Memory
ST BTA12 600C
12 A SnubberlessTM, logic level and standard Triacs