Answer from (microsoft):
in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout
create the value Scancode.Map of type REG_BINARY with the folowing data in
00000000 00000000 0300000000 3A001D00 1D003A00 00000000
Answer from (me):
#!/bin/sh
xmodmap - << EOF
remove Lock = Caps_Lock
remove Control = Control_L
keysym Control_L = Caps_Lock
keysym Caps_Lock = Control_L
add Lock = Caps_Lock
add Control = Control_L
EOF