I see these possible solutions:
a) you could be to write a small console app in c# which parses the file and write the data in a text file for your C++ code.
b) you parse the vmcx-file with some xml-parser in C++.
c) write some string search in C++ (a bit hacky)
d) advanced:
use C# in C++
e) advanced
use powershell in C++
The correct way would be e). If you do it, please write your results a article. I think, that a) would be the easiest way and c) a bit nasty.
Submit an article or tip