It works for me.
Here are the steps to take.
1) Open FMSE19. Go to File > Options.
Set your "Game Documents" folder. Then tick the "Enable IGA" checkbox.
2) Open FM19. Go to Preferences > Interface.
Hit the "Clear Cache" button. Then return to the same screen.
Below that button, tick option "Reload skin when confirming changes in Preferences" in order to make the "Reload Skin" button to appear. Then click that button.
3) Load your FM19 save.
4) Load the game in FMSE19.
5) Back to FM19, find any player and go to his Attributes screen.