I know this is slightly off topic, but i need help with Strike Commander's keystrokes


I just got Strike Commander on GoG (awesome!) but I am having a problem. I've tried 3 different keyboards and they all run into the same issue. The + and ~ keystrokes register as = and ` in game. So I am unable to access the increase throttle increment and cut engines commands.

How can I get Strike Commander (or DOSBOX rather) to register these keys as their SHIFT mod equivalents?