Is Flash supported in XMP?

                           std::string StrHexValue;

                           meta.GetProperty(kXMP_NS_EXIF, "Flash", &StrHexValue, 0);

This returns an empty string, when it should return a HEX value.

Whats' wrong in this syntax?

p.s. The same holds for InteroperabilityIndex Tag

Thanks,

Mikayel