I just saw your post and was about to comment there, but you beat me to it. I haven't tried crossposting yet, but I did get the tutorial to work in terms of adding users - AFTER reading the comments. Because apparently we're supposed to get that under Server Settings we're supposed to change the user name to the regular user name, with the added IJ, GJ, LJ or JF removed. I didn't, so thank goodness for smart people who comment, eh?
After you have the users I guess it's just a matter of selecting the ones you want to post to under Post to Multiple Journals. I hope, anyway.