I've been using Fusion 6 on my mid-2013 Macbook Air with a UK keyboard under Mavericks and then Yosemite to run Ubuntu 14.04 and Windows 7 virtual machines without any problems with key mappings (I have a custom keyboard layout for Windows which always used to work). With the change to Fusion 7 (I started with 7.0.1 then moved to 7.1) the SECTION/PLUSMINUS and GRAVE/TILDE keys have been transposed.
I fixed things under Ubuntu by editing the UK keyboard layout file in the OS (I can dig out details if anyone is interested) and I sorted out Windows by adding some custom key mappings in Fusion Settings (I did try the Language-Specific Key Mappings but they didn't correctly map SECTION/PLUSMINUS, leaving it as GRAVE/NOT, and the right-alt key didn't map the Euro and hash symbols to the 2 and 3 keys).
So why did this mysteriously change in 7.x after working perfectly well for over a year with 6.x? It's taken me a while to sort out the mess!