I have bought two months ago a new TomTom GO720. Now I have bought new 4GB MMC card and even everywhere is written that 720 supports SD and MMC cards, I am not able to work with that. I only found some troubles with using SDHC cards, but no topic abouts troubleshooting with MMC cards. My Windows XP explorer just still asks me to put the removable card in.... Should I return this card to the seller or is there some possibility use it in the future???