added the code that works. It is tested outside of StepMania

src/arch/InputHandler/InputHandler_MacOSX_HID.cpp

@@ -373,6 +373,50 @@ RString InputHandler_MacOSX_HID::GetDeviceSpecificInputString( const DeviceInput
 	return InputHandler::GetDeviceSpecificInputString( di );
 }
 
+// Modified from NESControllerInterface of Macifom project,
+// used under MIT license from http://macifom.googlecode.com/svn-history/r89/Macifom/trunk/NESControllerInterface.m
+// Used under MIT license from http://inquisitivecocoa.com/2009/04/05/key-code-translator/
+static wchar_t KeyCodeToChar(CGKeyCode keyCode, unsigned int modifierFlags)
+{
+	TISInputSourceRef currentKeyboard = TISCopyCurrentKeyboardInputSource();
+	CFDataRef uchr = (CFDataRef)TISGetInputSourceProperty(currentKeyboard, kTISPropertyUnicodeKeyLayoutData);
+	const UCKeyboardLayout *keyboardLayout = (const UCKeyboardLayout*)CFDataGetBytePtr(uchr);
+	
+	if( keyboardLayout )
+	{
+		UInt32 deadKeyState = 0;
+		UniCharCount maxStringLength = 255;
+		UniCharCount actualStringLength = 0;
+		UniChar unicodeString[maxStringLength];
+		
+		OSStatus status = UCKeyTranslate(keyboardLayout,
+						 keyCode, kUCKeyActionDown, modifierFlags,
+						 LMGetKbdType(), 0,
+						 &deadKeyState,
+						 maxStringLength,
+						 &actualStringLength, unicodeString);
+		
+		if( status != noErr )
+		{
+			fprintf(stderr, "There was an %s error translating from the '%d' key code to a human readable string: %s\n",
+				GetMacOSStatusErrorString(status), (int)status, GetMacOSStatusCommentString(status));
+		}
+		else if( actualStringLength == 0 )
+		{
+			fprintf(stderr, "Couldn't find a translation for the '%d' key code\n", keyCode);
+		}
+		else
+		{
+			return unicodeString[0];
+		}
+	}
+	else
+	{
+		fprintf(stderr, "Couldn't find a translation for the '%d' key code\n", keyCode);
+	}
+	return 0;
+}
+
 wchar_t InputHandler_MacOSX_HID::DeviceButtonToChar( DeviceButton button, bool bUseCurrentKeyModifiers )
 {
 	// KeyTranslate maps these keys to a character.  They shouldn't be mapped to any character.
@@ -402,6 +446,14 @@ wchar_t InputHandler_MacOSX_HID::DeviceButtonToChar( DeviceButton button, bool b
 			return L'\0';
 	}
 
+	// Use Quartz to translate device button to char
+	UInt8 iMacVirtualKey;
+	if( KeyboardDevice::DeviceButtonToMacVirtualKey( button, iMacVirtualKey ) )
+	{
+		UInt32 nModifiers = bUseCurrentKeyModifiers ? GetCurrentKeyModifiers() : 0;
+		return KeyCodeToChar( iMacVirtualKey, nModifiers );
+	}
+
 	return InputHandler::DeviceButtonToChar( button, bUseCurrentKeyModifiers );
 }