admins dont belong to usergroups or get forum ranks.. so they cannot get badges that way…
they can get special forum rank badges though – that is how we display them here…
by default usergroup badges are not shown in the forum… we show the forum ranks instead… but you can add them to your template files to display them…
see: http://codex.simple-press.com/codex/api/template-functions-and-the-api/display-template-functions/topic-view/sp_postindexusermemberships/
as to why special ranks dont show up, can you provide any more info? by default our themes include the special rank display… can you check the spTopicView.php template file in your sp theme and see if the function call sp_PostIndexUserSpecialRank() is still in there?