[SalesForce] Do FeedItem Triggers fire on the case feed “send an email” action

My organization has begun to use casefeed for cases and so far we've run into one problem: emails in the case feed sent by technicians to customers appear in the case feed, but do not get exposed to "AllUsers" in the FeedItem.Visibility property and thus do not get exposed in the portal.

We actually solved another problem with Feed Item Case Notes by using a trigger to analyze the feeditem, check if it corresponded to the case, then setting the its case status to investigating. However, oddly enough, the code that we tried to adapt to do both that case status update and the visibility trick does not even fire on casefeed email items…even though they appear in the case feed as a casefeeditem and export as feeditems from the data loader.

For the sake of completeness, here is a code sample from the trigger:

trigger FeedItemUpdateCase on FeedItem (before insert) 
{
    try
    {
        Set<Id> caseIds = new Set<Id>();
        List<Case> cases2Update = new List<Case>(); //cases we'll update.
        List<Case> casesToConsider = new List<Case>(); //cases we'll filter out

        for (FeedItem fi : trigger.new)
        {
            system.debug('FeedItems parent Id is: '+fi.ParentId);
            string strId = fi.ParentId;
            //If the item is a case.
            if (strId.startsWith('500'))
            {
                //add the case to our ones to update
                caseIds.add(strId);
            }
        }