Standalone electronic leadscrew (gearbox) mode for lathe

Hi,
at leats i got i running with my parallel Port setup.
One problem left: 
in the HAL are those  sections one for x and one for z

net x-control-type <= lathe_ui.control_x_type
net x-control-type => hm2_7i96.0.stepgen.01.control-type
net x-velocity-cmd <= lathe_ui.velocity_x_cmd
net x-velocity-cmd => hm2_7i96.0.stepgen.01.velocity-cmd

The problemis in the second and the fourth line
I don´t know how to switch this to the parport stepgen commands.
As far as i understand the Hal those are used for jogging with the cursor buttons, but maybe i am wrong.
Any ideas??

Thanks in advance
 

Will this work with only one stepper (on the main leadscrew)?

Yes but then the facing and taper function won`t work