[Libdlo] 3 monitor setup half way working

[golwin]

I purchased a Winstar USB->DVI adapter to enhance my dualhead-setup
with a third monitor (connected via VGA). So far I've got my Laptop
(running archlinux with awesome wm) with one external monitor. The
xorg.conf is almost default and dualhead is managed by xrandr. X is
started manually with startx

Within arch I installed the driver for the adapter via the AUR (Arch
User Repository) which contains udlfb 0.2.3 and
xf86-driver-displaylink. Next I modified xorg.conf according to the
information from the DisplayLink Wiki (and the linked blogs).

Two things were crucial:
- using /dev/fb1 instead of /dev/fb0 or an EDID-error pops up and X
won't start
- displaylink needs to be Screen 0 in the xorg.conf ServerLayout or
the displaylink driver will be unloaded

Executing startx now gives a cloned screen for the two old monitors
and an extended desktop on the new monitor. So far nothing was won
(besides one clone). Executing my xrandr command (which is also in
.xinitrc)

xrandr --output VGA1 --preferred --left-of LVDS1

brings no changes for the displaylink monitor, but makes my two old
ones one large streched screen (which is quite unusable due to
different resolutions). My attempts to let awesome wm know that
there is another screen to handle seperately (own menu etc..) didn't
work so far. Anyway I'm almost sure that this is something I don't
have to fix in the awesome-config (rc.lua), as my xrandr-command is
the same one that I used for my old (perfectly working) dualhead-setup.

Additionally dragging windows from or to the displayport monitor is
not working and xrandr -q (executed from the displaylink-monitor)
shows only the one monitor connected to the adapter.

Most stuff I've read so far was explicitly dealing with Ubuntu and
gdm. Is anyone doing about the same as I am? Or anyone dealing with
a similar problem (cloned or streched desktop, but not properly
extended)? I would be thankful for ideas and comments :)