missing key information in emulation mode

[Thomas Bock]

When a SQL table is opened via the prefix file, then the FIN() function doesn't return any key information. The returned string has a length of 68 bytes only.
We work in BBx-mode and fin$(86,385) is required in order to use KGN(). And KGN() is frequently used in our application.
I don't know any other way to generate key values. If there is no alternative, then I want this to be added.