I have found an Internet article entitled _Custer's Italians_, by Vincent A. 
Transano (originally appearing in the June 1999 issue of _Wild West_ 
magazine).  

To quote briefly from the article:
"The full complement of the 7th Cavalry in June 1876 was 43 officers and
793 enlisted men. Of that number 473 were native born and 320 foreign born. 
The two largest foreign-born groups in the regiment comprised 129 Irish and 
127 Germans. The remaining 64 foreign born were drawn from 14 other 
nationalities, including six Italians. 

These were:
 
1st Lt. Charles Camillus DeRudio (aka Count Carlo Camillo Di Rudio)of Company 
A;
Private Augustus L. De Voto (a k a Augusto De Voto) of Company B;
Private John James (a k a Giovanni Casella) of Company E;
Private Frank Lombard (aka Francesco Lombardi) of the regimental band;
Private John Martin (a k a Giovanni Martini), trumpeter of Company H; and
Chief Musician Felix Villiet Vinatieri (a k a Felice Villiet Vinatieri) of 
the regimental band."

The article goes on to discuss the Italians and their activities in much more 
detail.

<A HREF="http://columbiad.com/wildwest/articles/1999/06992_text.htm">Custer's 
Italians - Full Text: June '99 Wild West Feature</A> 
http://columbiad.com/wildwest/articles/1999/06992_text.htm
=====================================================
I would append : ...Unlike native-born Americans, Irish and Germans, the 
Italians were too few to constitute a group or subculture in the regiment...
The Italians shared many of the social disadvantages of the Irish as well as 
some unique to themselves. They, too, were Roman Catholics; they were poor 
and, as southern Europeans, tended to be short and swarthy, and thus further 
removed in appearance from the northern European norm. Further, they came to 
the new country speaking a foreign tongue. The only advantage the Italians 
had over the Irish was that they were so few that they were not objects of 
such organized discrimination.... 
 
The Italians in the 7th Cavalry evidently recognized their social 
disadvantages and took steps to lessen the obvious differences between 
themselves and native-born Americans. All six anglicized their given names, 
and three of them did the same to their surnames (or in the case of John 
James, adopted an new surname)....

...The Italians... had no urge to maintain their cultural identity, since 
they belonged to no ethnic subculture. They simply desired to lose themselves 
in the general population and become Americans....