I actually didn't try it when I got my Windows 7 laptop since I wouldn't be messing with shn files on there or uploading anything from the laptop.
Good news though, since I asked a lot of people I know in addition to posting here and on the etree forums, one guy sent me the actual mkw icon and the md5 icon I'm used to seeing when I had XP, so just like the flac icon I already got from a taper friend, I'll associate these with my shn and md5 files.