He was leading the decisivie attack of the french forces on the allied center at Austerlitz. Why is he not in the game? Which commanders in the boardgame where under Soults command?

Order of Battle at the Austerlitz campaign

IV Corps
Marshal Nicolas Jean de Dieu Soult
Strength: 23,600 men and 35 guns.

1st Division - General of Division Louis Vincent Le Blond de Saint-Hilaire
10ème Régiment d'lnfanterie Légère
14ème Régiment d'lnfanterie de Ligne
36ème Régiment d'lnfanterie de Ligne
2nd Division - General of Division Dominique Joseph Rene Vandamme
24ème Régiment d'lnfanterie Légère
4ème Régiment d'lnfanterie de Ligne
28ème Régiment d'lnfanterie de Ligne
43ème Régiment d'lnfanterie de Ligne
46ème Régiment d'lnfanterie de Ligne
55ème Régiment d'lnfanterie de Ligne
57ème Régiment d'lnfanterie de Ligne
3rd Division - General of Division Claude Juste Alexandre Legrand
26ème Régiment d'lnfanterie Légère
3ème Régiment d'lnfanterie de Ligne
18ème Régiment d'lnfanterie de Ligne
75ème Régiment d'lnfanterie de Ligne
Tirailleurs du Pô (Italian light infantry)
Tirailleurs Corses (Corsican light infantry)
Light Cavalry Division - General of Brigade Pierre Margaron
8ème Régiment de Hussards (Hussars)
11ème Régiment de Chasseurs à Cheval
26ème Régiment de Chasseurs à Cheval
Corps Artillery - 35 guns (mostly 12pdrs)

Good point. Yes, Soult's corps was historically much larger than the other corps, so it actually consists of, in game terms, the _Divisions_ of St. Hilaire, Vandamme, Legrand, any detached cavalry brigades / regiments, and the 2 artillery units; the former are called 'corps' for game terms because they moved independently & with different missions during the battle. They were placed under Soult for administration & deployment purposes.

Soult is not in the game because his division commanders are instead. The game only supports a single level of command. On the Allied side, Kutusov and Buxhowden aren't in the game either, for the same reason.

Essentially, the top-ranking commanders who were physically present with the soldiers under their command are the ones included. Soult's 3 divisions were in different parts of the battlefield, spread out over much too large of an area for Soult to be with them all. Soult seems to have spent most of the battle at Napoleon's HQ.

Or put another way, in a team game, YOU are Soult.