Pues me respondo a mí mismo. No va a funcionar. Esto es lo que ponen en Nikon USA para el 800mm 5.6 E, que tiene el mismo tipo de diafragma:
"Electromagnetic diaphragm mechanism is incorporated for enhanced stability in auto exposure control during continuous shooting even when the teleconverter is used (Not compatible with the D2 series, D1 series, D200, D100, D90, D80, D70 series, D3000, D60, D50, D40 series, 35mm film cameras)"