Your best bet is to, as you have already said, clever mg play (covered by grens so you can faust divers) into fast 222 which usually hardcounters any light vehicles.
AAHTs come usually later, after your tier 2. Your best bet then is a pak. AA halftracks have horrible pathing and die to 2 paks shots so he wont be able to push with it at all.
A clever teller mine is a good answer too.
I know that it is much more easily said than done, that's why I recommend you to upload a replay where you are struck against this particular playstyle, so we can review it and give you more valuable feedback.
Cheers,
Hector
This is great
Another annoying TIP.
Hide your granadiers!!! Use the MG/MORTARS AS DECOY for the pesky gameplay about rushing light vehicles When they come running to kill your weapons teams
*) appear with your granadiers from the fog of war,and faust it!
*) if the MG have Veterancy get AP bullets and hit them ( Sustained fire over light vehicles can do some damage but is minimal, useful maybe to use one faust less).
*) use your mortars over the fausted vehicle., two lucky mortar shots can replace a faust (about).
*) if the Allied player was dumb enough to send the vehicle alone ( without any kind of support ).
*) chase it aggresively with your granadiers ¡ BUT BE CAREFUL MGs could be there ! if you get a good recon of that area that the tank is retreating a good smoke Coverage using your mortars can give enough time to kill them.
Note: Be careful regarding to MG positioning after the config change you can receive visits from enemy infantry 2 MGs is a must agaisnt USF/SOV enemies.
Thanks!