Isobasins tool-using flow pointer and flow accumulation raster

[csmemoe-aquaveo]

The inputs for the Isobasins tool include a pit-filled DEM and the target basin size in grid cells. The output is a raster that attempts to divide the DEM into basins of equal size. It seems that the Isobasins tool currently does not have an option to use a flow pointer and flow accumulation raster. However, to derive streams for the Isobasins, I'd need a flow direction and flow accumulation raster. It seems like the option to use flow pointer/flow accumulation rasters as input to the Isobasins tool was an option that was previously available. My question is whether there is a way for me to use flow pointer and flow accumulation grids as input to the Isobasins tool. And if not, is there any way to output the flow pointer/accumulation grids from the Isobasins tool so I can create a vector stream file? Is the only way to do this to modify the Isobasins code?