FVWM: How to make xclock transparent?

[for.register for.register]

Hi, all

Is it possible to make xclock transparent?

Here is my config, it doesn't work.
Colorset 8      RootTransparent
Style  XClock   !Title, !Borders, Colorset 3, NeverFocus, \
WindowListSkip, \
                CirculateSkip, StartsOnPage 0 0, Forecolor Colorset 3