The image is the cover art for one of the DVD versions of "March or Die" with Gene Hackman and Terence Hill, and reflects more the last stand events of the movie rather then any historical event.

For artillery a simple mountain gun like that included in this strelets set from the RTW would work:

http://www.plasticsoldierreview.com/Review.aspx?id=1907

it may even be possible to use some of the gunners or convert them to north african gunners(hooded coat)...
You should note that when older accounts refer the use of a "Hotchkiss Gun" its most likely refering to a small gun of this kind or a gatling type ship gun not the famous french MG.

summer 1918 somewhere in N-Africa:
"Pochelu resumed his advance with the legion company(mule company) once more behind the center in reserve.
At perhaps 2.30pm the column came under heavy attack and there was "violent fighting before the units could deploy" and the machine begin to function.
On the right the Senegalese fell back, the legion company moved forward and charged to fill the gap in the fighting front, but tribesmen infiltrated bettween the platoons of Senegalese......."

At first it sounds line any desert battle untill you realise its being fought in dense undergrowth in an extensive North African Oasis!

Source: Our Friends Beneath the Sands, Martin Widrow, Recommended :wink:

My younger brother was irritated all the time because of this same issue but after I consulted them for him, he feels a lot better and believe me every single issue is solved! tractor haulers near me