Mr. Camillo,
As noted in vol. II of Thunder on the Danube, p. 352:
3rd & 4th Battalions, 6th French Line Inf Regt (1,454)
3rd & 4th Battalions, 14th French LIGHT Inf Regt (1,352)
4th Battalion, 101st French Line Inf Regt (681)
3rd Battalion, Regiment Tour d'Auvergne (840)
4th Battalion, Corsican Chasseurs (?)
1st & 2nd Battalions, 1st Neapolitan Light Inf Regt (983)
one squadron, 1st Neapolitan Chasseur a cheval (265)

Although his order of battle had changed by late summer, the following may be of interest:
Situation for Miollis' Division in Rome as of 15 August 1809 (présens sous les armes in parentheses):
French
* III/14e Léger (696)
* 2e and 7e Companies/2e Artillery (153)
* Train (11)
Italian
10th Company/Italian Artillery (76)
Neapolitan
II/3rd Line (614)
I and II/2nd Light (939)
1st Chasseurs, all four sqdns (510)
Train (56)
No indication of type/number of guns.
GB Radet, Gendarmerie Impériale (97 + 148 detached)

Source: Service Historique de la Défense, C4/11