OK, now I’ve downloaded your sample, I see you need three dates, or rather the same date in three different formats. You can do that in the template, rather than using &dateSource, &dateFormat and [+date+]. Instead, you use PHx to modify the output of your placeholders.
If your date is in a placeholder called myDate, this would mean a template something like:
<h2 style="padding-top:10px;">[+title+]</h2>
Published on
<div class="date">
<div class="month">[+myDate:date=`%b`:ucase+]</div>
<div class="day">[+myDate:date=`%d`+]</div>
<div class="year">[+myDate:date=`%Y`+]</div>
</div>
[+summary+]
[+link+]
PHx is already built in to Ditto, so you don’t need to install the whole plugin. Details of its operation are at
http://wiki.modxcms.com/index.php/PHx

KP