Configuring A rotary axis to substitute for the Y axis

I have a home build 3 axis gantry machine and have constructed a horizontal rotary axis that I want to be able to substitute for the normal Y axis. Stepconf only seams to support XYZ and XYZA configurations. What is the best way to handle such a configuration? ( info: I am using Vcarve pro for design and code G generation ).

Do they have an axis substitution tool path option?

On the vcarve side I can define the rotary axis. Just not sure what to do in stepconfig for the linuxcnc side.

It may not look right in the preview window, but I don't see why it would work.
An a move is an a move no matter where the rotary is

Just some issue with degrees vs linear measure, if it can wrap on a rotary axis, if I will have issues with limits at 0/360, if I can ignore limit switches for that a axis. Just seems like a lot of things might be taken care of if it new it was a rotary axis. Maybe I can use the XYZA and just not define Y and set A up with those ports. Just wanting to see if someone has worked through it already.

You would have a y0 move to put you on center then drilling for example

G90 g0 x-5.y0a0
G81 z-5
A90
A180
A270

Angles are angles