Mesa 7I76 + 7i78 setup questions

I am hoping someone can help me understand how to setup a 7I76e with a 7i78
I need the 5 extra step generators

can this be connected with the default 7I76e firmware ?
how do I figure out the pin assignment so I can map my Axis to the 7i78 ?

I tried just changing the hal file
loadrt hm2_eth board_ip="192.168.1.121" config=" num_encoders=1 num_pwmgens=0 num_stepgens=5 sserial_port_0=00xxxx"

to increase the number of stepgens, but linuxcnc throws and error.

I think the 7I76 is not detecting the 7I78

any help people could offer would be welcome

Thank You
Calvin

freeby.mesanet.com/7i76e_7i76x1_7i78x1D.bit

Should be close ( Note that the 7I78 only has 4 Step/Dir outputs so you end up with a total of 9 Step generators )

Note: the 7I76E cannot detect the 7I78, the 7I78 is a passive BOB that basically just buffers signals
(and provides an isolated analog spindle interface) The additional hardware (stepgens etc) need to be
built into the 7I76Es FPGA with firmware that matches the 7I78s I/O connections (like the firmware above)

Thank you this is exactly what I needed info wise