Lenny. How to start X from console with a chosen DM?

[Mark Goldshtein <mark.goldshtein@gmail.com>]

Debian 5 Stable.
System installed from KDE CD ISO. Graphic logon screen is stopped by

# sysv-rc-conf kdm off

So the system initially boot into plain text console. WindowMaker
display manager was added. Now I am trying to start X session with
WindowMaker

$ exec startx WndowMaker

X doesn't start at all. If I say:

$ exec startx

Then KDE X session successfully started.
Would you please to explain, how to start X session with WindowMaker
DM in Debian?

-- 
С Уважением,
Марк Гольдштейн

Sincerely Yours'
Mark Goldshtein