Will take a closer look at that and let you know!
I think there's an intermediate solution for that. You could use a "Character" Textformat. You can create one in "Lay Options" :arrow_right: "Textformats". Add a new Format and as the Format Type, choose "Character". You will have a "letter-spacing" field for your new format!
Now when you apply that Character Format to words within a text-block, those words should have the correct letter spacing.
Edit: fixed in version 1.022