Unfortunately, that’s not something I had in mind when I originally built the plugin, so there isn’t a convenient hook to switch the ordering – it’s hard coded to order by the publication date of the posts …
However, you can hack the existing plugin if you really need this functionality now.
Around line 63 of /lib/class.wp-publication-archive.php you can see where the default arguments are specified to query for publications. Find the line 'orderby' => 'post_date', and change it to 'orderby' => 'title',. Then find the line 'order' => 'DESC', and change it to 'order' => 'ASC',.
I will also try to work this functionality into the next version, but please know that whatever changes you make today will be lost when you eventually upgrade.