Xorg + DH: device presence

[elpollodiablo]

Dear all,
I'm a gentoo laptop user and sometimes I need to attach a projector to my pc and give a talk. I have 3 profiles in my xorg.cof: single head, dual head, dual head (projector). I wrote a small script that, at boot, lets me select what profile I wish to use.

Everything works perfectly, but if X/gdm is started without the second monitor attached, dual head does not work.
Moreover, X sais that it did not find the second device (not the second monitor!).
After restarting X/gdm, everything works, but this solution is not satisfactory since I loose time + I need to restart applications etc.

Any suggestion? Is there any line I could add to my xorg.conf in order to force the nvidia drivers to start the second head also if no device is attached?

Many thanks,
Michele

ps: let me know if you need to give a look at my xorg.conf