Puede que hoy salga la versión 1.3 que arregla el gamestate a 128k que fue incluido en el 1.2 pero que no permitia a los modders sacar el máximo provecho, se ha solucionado el problema de las guids del PB (ahora saldran los 32 caracteres) y hará que funcione mucho mejor 
y el parche también añadirá pequeña cosillas que aun no se han desvelado. El parche ya está subido en varias webs, pero aun no es posible su descarga.
Actualizado
Ya ha salido el parche aunque no de manera oficial, aqui teneis un par de mirrors por si alguien lo quiere probar y el changelog en inglés:
http://rapidshare.de/files/22538267/CallofDuty2Patchv1_3.zip.html
www.4gclan.com/CallofDuty2Patchv1_3.zip
The Call of Duty 2 1.3 patch is an all-inclusive installation, containing all of the previous updates from the 1.2 patch and the 1.01 patch. Information about updates included from the earlier 1.2 and 1.01 patch can be found further down this document.
IMPORTANT NOTE: Use of the in-game console is not supported by Activision®. Please do not contact Activision Customer Support with issues that arise from using console commands in-game.
NOTES FOR MOD USERS:
- It is recommended that any user modifications that have been installed to the Call of Duty 2 directory be removed before installing this patch. These modifications are not supported by Activision and may not be compatible with some of the new features that are included.
- Call of Duty 2 does not support mods that have spaces in the mod's folder name. Be sure that the folder that contains your mod does not have spaces; otherwise users will not be able to download the files. For example, a mod in a folder called "My Mod" would be invalid, whereas "MyMod" or "My_Mod" would work.
MULTIPLAYER FIXES
-Raised the gamestate from 16k to 128k
-Added loading bars to maps mp_harbor and mp_rhine
-Addressed the PB GUID issue where players were not being assigned PB GUID's of exactly 32 characters.
mp_rhine map changes:
-Fixed player getting on top of broken wall and seeing through second story of bombed out building.
mp_harbor map changes:
-Reduced overall fog density
-Fixed missing water texture
-Fixed player not being able to shoot through lower portion of the first gap in a railing found on east side of map.
-Fixed player not being able to shoot through lower portion of railing found on east edge of map.
-Fixed a partially floating crate and a couple holes in sandbags.
NOTE - When benchmarking Call of Duty 2 using "timedemo ", the first few frames are
artificially slow. You will get more accurate results by using a spreadsheet program to
process the values in "main/demos/timedemo__mode_.csv".
The first column is the frame number, and the second column is the number of
milliseconds spent in that frame. Just ignore the first ten or so rows.
The average framerate is 1000 divided by the average of the remaining rows.
