Ubuntu desktop 12.04 and virtualbox - is it possible to set mobile resolution ? ( e.g. 1440x2560 )

Question

I installed ubuntu desktop 12.04 with guest additions on virtualbox.
I try to set resolution with custom /etc/X11/xorg.conf config.

Section "Device"
    Identifier "Device0"
    Driver     "vboxvideo"
EndSection

Section "Monitor"
    Identifier "Monitor0"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "Device0"
    Monitor    "Monitor0"
    SubSection "Display"
        Modes "1440x2560"
    EndSubSection
EndSection

The problem is the following:
Ubuntu allows me to set resolution like "2560x1440", but does not accept resolution like "1440x2560".

It is possible to "hack" this?
Thank you.

Answer 1

I fixed the problem)

New xorg.conf:

Section "Device"
    Identifier "Device0"
    Driver     "vboxvideo"
EndSection

Section "Monitor"
    Identifier "VGA-0"
    Modeline "1440x2560_60.00"  318.00  1440 1568 1720 2000  2560 2563 2573 2651 -hsync +vsync
    Option "PreferredMode" "1440x2560_60.00"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "Device0"
    Monitor    "VGA-0"
    DefaultDepth 24
    SubSection "Display"
        Modes "1440x2560_60.00"
    EndSubSection
EndSection

Also notice that Monitor Identifier changed from "Monitor0" to "VGA-0".
If i don't use identifier "VGA-0" -> config does not work.