I've never tried it personally but when you look at the available campaign files it should not be hard to do this with a text editor if you have the individual scenarios already available:
The structure of a .cpd file would be something like (I was looking at a Modern War campaign as example):
Code:
<Campaign title>
<Name of the side the player plays>
<path to preview picture relative to game main folder>
<Start - not sure if this is free text or if it has to follow a certain formatt>
<End - not sure if this is free text or if it has to follow a certain format>
<Leader unit from the .oob who represents the player>
<Campaign description text>
<List all paths to .scn files which shall be part of the campaign in a separate line each>
Example from MW:
Code:
Operation Phantom Fury
American
campaign/Fallujah.bmp
Start: 09/11/04
End: 10/11/04
106 13 Cap Robins
With the Sunni Arab guerrillas evicted
from Samarra, the Coalition turned its attention toward Fallujah.
After the CPA called off the Marine offensive to destroy the
Sunni insurgents in April 2004, Fallujah had once again become
a sanctuary for Sunni Arab insurgents. For the Coalition and
the IIG, the idea of holding elections while a large city near
Baghdad remained in enemy hands was untenable. Coalition forces
sealed off the city and urged all non-combatants to leave. This campaign
covers the actions of Cap Robins as he leads the Alpha Company of the
TF 2-7th Cav against the insurgents in Fallujah.
campaign/009.Fallujah-B.scn
campaign/010.Fallujah-C.scn
campaign/011.Fallujah-D.scn