Hi,
From Template settings you cannot. But you have 3 alternatives:
- You can edit Helix Ultimate plugin code (php) and add what you need. I talk about file:
plugins\system\helixultinate\overrides\layouts\joomla\content\social_share.php
- OR, you can disable default Social Share icons from Template Options, then find on JED Social Share plugin (that have all you need), install and publish it.
- Or, you can hire somebody who will write you a simple social share plugin that include needed icons.
2 and 3 is better than (1) becuase you don't have to be worry about Helix updates that will delete your work/modications.
For today, it's all I can help.