kernning is not exported from the Private Use Area.
How did you verify this?
I checked while making the icon font.
It works well in the file, but the extracted file deleted all the kernning in the PUA area.
In what application are you testing your font? How did you verify that your kerning is not exported?
Reopened the font file in Glyphs.
The Latin letter had kernning left, but it was deleted from glyph in the PUA area.
I tested it on both OTF and VF files, and I checked the same status.
That is not a good way of testing. Please use a app like FontGoggles or browser based tests like fontgauntlet.com
Importing a binary font is tricky. And not always fully possible. But imprints kerning should work. Can you send me the .glyphs file and the .otf you exported?