There is, but it involves editing one of the pack files and changing the tax settings.
There is a post about it here in this forum. You just need to find the version 3 beta of the pack file manager (google is your friend). It's a bit tricky given that you are changing a file but it works.
Pressing f1 doesn't activate the trainer for me. I tried activating it in the game's main menu and on the trainer itself in desktop. Yet none of those options seem to work for me. The trainer says that my num lock is turned off when it's not. Any help is appreciated.