You are correct, neither Parallels not Fusion can currently read the Bootcamp partition on the 12" Macbook, regardless of Windows version installed. From their forums:
1. VMWare engineer has explained that the problem is with the 4KB sector size on the new SSD, but Fusion expects 512B size so the partition table isn't read properly. No ETA for a fix.
2. Parallels is only slowly waking up to the problem with the usual clueless level 1 support knowing nothing about it. No indication yet of the source of the problem or any fix in the works.
Looks like Fusion might get a fix first, but personally I find that Parallels generally runs smoother and with fewer bugs, so I'm holding out. I shall be quite annoyed if either needs another paid upgrade though.