When you say bitbang, do you mean connect to the X3 connecter next to the FTDI chip?
If so, I don't know.
What I would do instead is load the ISP programmer sketch into the Duemilanove and let the sketch program the Leonardo.
You would connect:
Programmer Leonardo
SCK SCK
MOSI MOSI
MISO MISO
+5 +5
GND GND
D10 Reset