Thanx for replying.
The document was made in OO writer, and converted to epub with writer2xhtml. In Sigil I make last minute replacement when needed. I check my epubs with iBooks and ADE. You’re right: ADE doesn’t recognize letter-spacing. But Ibooks does and so does the Calibre ebook viewer. I use Calibre to upload te pub to my Kobo Glo. I do not use ADE.
I know letter-spacing works on kepub. I can see the spacing between letters. The spacebars are discarded some how.