After having played this mission a couple of times I don't think winning as the Russian is the point. The default defensive position is not the best, not being able to emplace the AT guns is unfortunate and you are at a disadvantage number-wise.
The APCR rounds for the AT guns do work. I knocked out the PZIII's early on my second go at this, on the first I let the battle run it's course with little input just to see what would happen, you men were correct the Kraut's very accurate at tank gunnery. The ATR's do disable the PzII's , they were not too happy to attack the trench without the PzIII's untill the ATR's were gone or suppressed.
The Russian's lose anyway, it sucks but there it is. The mission briefing is quite specific, it doesn't say knock out the tanks or kill the enemy infantry it says in effect fight and hold the position, you die in the process, but War is all hell as Gen Sherman says.
I am a long time ASL player. If the setup was the same I think I would have a decent chance as the Russian playing this mission as an ASL scenario. The rate-of-fire and armour penetration of the APCR rounds of the 45L ATGs would take care of those Panzers pretty quick. Two sections of German infantry against a dug in Russian squad supported by two AT guns and two ATRs would be a tough nut to crack without armour support. But this ain't ASL.
No, its a brand new computer war game we all have little experience with. The modding community hasn't had a crack at this one yet. So fight this mission as best you can, learn a thing or two about the controls and how the game works and carry on.
Sgt Major. Out.