Newbie Help Making or uploading counters to Panzer Blitz for Dad

My dad loved this game as a kid and I got it downloaded for him but I know he would really love it if I could add in counters that arent available in the game, I dont know if theres like a place to add a game piece or upload an image for it, but I would really love to make it happen for him. Sorry in advance if this is a dumb question, I have very little experinece with this and just wanted to see if it was possible.

With a Vassal game module you can add what you like (edit mode). Maybe the built in ‘NATO’ standard counter builds can help. Appreciate that Panzer Blitz uses images for the counters rather than the standard NATO symbols, and perhaps you can scan these in for further use.
However, what type of additional units do you want to add in? The game, rules, scenario setups are pretty much set.
Now if I remember when I lost my Panzer Blitz and where then I’d be happy to get it back. At least I’ve still got Panzer Leader.