The built-in card readers are not SDHC-capable. Software will not help you since there is no SDHC-interface in the module.
If you need to access SDHC-cards you will have to get either an external cardreader or one for the expresscard-slot.
If you are looking for such a device, and need to write to a card, be careful:
Though most of the so called "cardreaders" are able to write to cards there are also read-only-devices.