Windows: accessing an index with non-ASCII path

Hi,

Would someone know the appropriate magic to transform a Unicode Windows
path into something that Xapian can use with its open() calls ?

The index is relative to a user directory, the user is Korean, with a
Korean user name, the home directory is retrieved through a Windows Unicode
interface, the path to the index computed from this, and I can't find a way
to open it (tried misc variations of WideCharToMultiByte() with no
success...

Cheers,

jf