Xorg startup with serial console

Hi,

i want to start an xserver on a sun workstation that boots using a
serial console. The plan is to attach a monitor to an otherwise
headless machine and provide mouse and keyboard via synergy.

On a standard boot with an attached keyboard, i can start the Xserver
and it says it uses a console like this:

[   550.602] (--) Using wscons driver on /dev/ttyE1 in pcvt
compatibility mode (version 3.32)
[   550.602] (--) using VT number 2

But when i do the boot via a serial connection without an attached
keyboard, i can not start the Xserver.
The error is that it would be missing a console driver:

[  1043.586] (EE) xf86OpenConsole: No console driver found
        Supported drivers: pccons (with X support), pcvt, wscons
        Check your kernel's console driver configuration and /dev entries(EE)

I am currently not using an xorg.conf on this machine, which is why i
wonder that the autoconfiguration drops this error.

Am i missing a driver or do i need to provide specific xorg.conf settings?

Regards,
Connor