I would like to suggest the Sd.Kfz.250/7 Ausf. B armed with the 8 cm Granatwerfer 34, a Mortar.
It would mobilise the allready in game available mortars, with a far greater ammo amount.
But back to the Vehicle itself:
History:
The AHA IN6 (Inspectorate of Motorized Troops) requested a small armored Half track to accompany tanks on the offensive and perform auxiliary mission in 1939. These tasks were (not limited to) Scouting, mobile HQ, command vehicle, radio vehicle, forward observer and ammo carrier. And be smaller compared to the then also in development Sd.Kfz.251, its bigger brother.
It was an development of the Sd.Kfz.10, which was made by Demag, who was allready recognized for their expertise in very small and fast half tracks, which was recently accepted into service. Of these Sd.Kfz.10 were around 12.000 produced until 1945 and additional 6.628 of the armored version Sd.Kfz.250. The armored body was designed and produced by Büssig-NAG abd called Leichter gepanzerter Mannschafts Transportwagen (light armored troop transporter) with the number Sd.Kfz.250. Build from 1939-1944.
The Sd.Kfz.250/7 was both an 8 cm Granatwerfer 34 carrier as well as ammo carrier, designed to support the artillery and infantry units.
Later in the war, a new armored hull was introduced, the Ausf. B, this was a simplefied and improved version that streamlined the armor platings to simplefy and speed up production as well as make it slightly lighter (about 200-300kg) and reduce the target area from the front, as the sides were now straight plates with the addition of 2x 8mm Armored boxes as also allready seen on the Sd.Kfz.251. These 2 versions were then known as Ausf. A and B.
The Gun:
8 cm Granatwerfer 34 (Actual diameter 8,1 cm) 66 Rounds storage and AA Mg 42 on the AA mount at the back.
Fire Rate 15-25 Rpm Highest velocity 174 m/s Elevation 38,8° to 88,9° (So you can even hit right in front of you.) Traverse 8,89° to 14,4° (Depending on the elevation)
Ammo:(Click on the names to show)
There were multiple rounds available and captured French and Nether 8,14 cm rounds could also be used, however i will only mention the 3 game play wise interesting ones:
8 cm Wgr. 34 He 32,9 cm length 3,5 kg 0,565 kg Fp.02 and Np.10 Filler (723,2g TnTa) Filler 174 m/s 2400m Range
8 cm Wgr. 34 Nb Smoke 32,9 cm length 3,5 kg 0,22 kg Filler 0,5 kg Smokestuff 174 m/s 2400m Range
and a special round:
8 cm Wgr. 40 He 56,4 cm length 7,5 kg 2,5 or above 3 or ~5 kg Fp.02 and Np.10 Filler (3,2 to 6,4 kg TnTa) ? m/s 950m Range
The Vehicle:
Sd.Kfz.250 Ausf. B
Length / Width / Height: 4,56 m / 1,94 m / 1,66 m
Crew: 4-5
Engine: HL 45 TRMK 100 Ps at 2800 rpm
Speed: Max speed by trails 75 km/h (drivers were told to not go faster than 65 km/h duo wear)
Weight: 5,67 Ton
Armor:
Front 14,5mm angled, engine deck 8mm
Sides 8mm + 8mm (Armored Storage Bin)
Back 8mm
Source:
Geschossringbuch II
Thomas L.Jentz, Hilary Louise Doyle - leichter Schuetzenpanzerwagen (Sd.Kfz.250) Ausf.A & B History of Production
Die Halbketten-Fahrzeuge des deutschen Heeres 1909-1945