I wouldn't suggest using dd because the geometry will be different, what I would suggest is that you backup the Microdrive contents by whatever means you like, take it out and using a Linux box tar off the contents then create your file systems on the new device and tar them back using that same Linux system. Then fit the new device with the file systems that have been prepped on the Linux box.
Make sure you use the p flag when tarring back though because you want to preserve userids and permissions etc.