I made a mistake and didn't notice that the weekday abbreviations (S, M, T, W, T, F, S) were not showing up along the top row. I finally figured out what was causing that: the phrase group that's loaded needs to include 'calendar'. And the $phrasegroups variable needs to be updated before global.php is included.
So for example at the top of index.php you'll see:
PHP Code:
$phrasegroups = array('holiday');
which needs to be
PHP Code:
$phrasegroups = array('holiday', 'calendar');
in order for the days to show up.
There's probably a nice clean way to do this in vbulletin that is more modular and doesn't involve editing code in as many places, but for me this is now working.
Thanks for piecing this together! It works very well.