[User 55003]

I had a closer look and got it working. Turned out to be fairly simple.
You could go crazy and turn the added code in a module to service other requests but seeing as I use the builtin kodi edit I think I'll leave it here and let you tinker if you like.

Here is the code I added to get it working.

PHP Code:

elif actionstring == "sorttitle" :
    json_request = xbmc.executeJSONRPC('{"jsonrpc": "2.0", "method": "VideoLibrary.GetMovies", "params": { "filter": {"field": "title", "operator": "is", "value": "'+xbmc.getInfoLabel('ListItem.Title')+'"}, "properties" : ["sorttitle"], "sort": { "order": "ascending", "method": "label", "ignorearticle": true } }, "id": "libMovies"}') 
    json_request = unicode(json_request, 'utf-8', errors='ignore')
    json_response = json.loads(json_request)
    if json_response.has_key('result') and (json_response['result'] != None) and json_response['result'].has_key('movies'):
        for item in json_response['result']['movies']:
            sort_title = item['sorttitle']
    if sort_title == "":
        self._edit_db_string(xbmc.getInfoLabel('ListItem.Title'),self.TYPE,"sorttitle")
    else:
        self._edit_db_string(sort_title,self.TYPE,"sorttitle") 


Here is the default.py file
default.zip