Repurpose RS-422 on 7i76e?

I need to add a 6th step generator for my spindle (it is a servo spindle)... Am I understanding how bit file generation works (Xilinx Webpack design tool, VHD files, etc) that I could just replace the
with something like
?

Also, in the VHD files, where are the 48 standard I/O ports programmed? I am not quite following where the last 3 rows of the 7i76e are programmed in the project..

Thanks all

Looking at the file more (and some other docs)..

Maybe change

Delete:
Also Update: To:
??

SSerial 0 on a 7I76E goes to the field I/O section so not useful for step/dir
( the 48 field I/O points are accessed via this port )

SSerial 1 goes to the expansion serial port (so you could get 1 output only)

If you want to add additional stepgens, they should be added to one of the 7I76Es
parallel expansion connectors, for example using the 7i76e_7i76x1_5abobD.bit
firmware allows you to use one of the common "Mach 5 Axis" breakout boards
connected to P1 and giving 5 additional buffered 5V step/dir channels

Gatcha, I am already having to add a 7i89 for encoders, and I have a spare bob, and was trying to find a way to NOT have to add it too... But if that is the case, that is the case.. I figured no matter what I did I would have to build a custom firmware..

I am guessing then I can't repurpose TB4 to Step and Direction either as it has special analog IO Pins? (Spindle is a servo so it runs better off step&direction than over PWM especially with rigid tapping, and again that would end up saving me an extra Bob for 1 Step and Direction generator )