Changed the 'plural' function so that it doesn't ruin the captalization of your string. It also take into consideration acronyms which are all caps.
diff --git a/system/helpers/inflector_helper.php b/system/helpers/inflector_helper.php
index 4cd7486..3042202 100644
--- a/system/helpers/inflector_helper.php
+++ b/system/helpers/inflector_helper.php
@@ -82,18 +82,17 @@
 {
 	function plural($str, $force = FALSE)
 	{
-		$str = strtolower(trim($str));
 		$end = substr($str, -1);
 
-		if ($end == 'y')
+		if (preg_match('/y/i',$end))
 		{
 			// Y preceded by vowel => regular plural
-			$vowels = array('a', 'e', 'i', 'o', 'u');
+			$vowels = array('a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U');
 			$str = in_array(substr($str, -2, 1), $vowels) ? $str.'s' : substr($str, 0, -1).'ies';
 		}
-		elseif ($end == 'h')
+		elseif (preg_match('/h/i',$end))
 		{
-			if (substr($str, -2) == 'ch' OR substr($str, -2) == 'sh')
+            if(preg_match('/^[c|s]h$/i',substr($str, -2)))
 			{
 				$str .= 'es';
 			}
@@ -102,7 +101,7 @@
 				$str .= 's';
 			}
 		}
-		elseif ($end == 's')
+		elseif (preg_match('/s/i',$end))
 		{
 			if ($force == TRUE)
 			{