How to handle cash portion in Firecalc?

[downrod]

I have ran my numbers in Firecalc, but I do not see how to account for the cash portion of my portfolio.
I have included the cash portion in my portfolio total on page one, but in the investment section, I can only adjust the % of the portfolio that I have in equities. I think the formula assumes that the remainder of the portfolio is invested in bonds. How do you handle the cash portion? My concern is that the formula assumes a higher rate of return for this portion than I would actually be getting with cash

 

[Dtail]

For my cash, I just use the bond default. I suppose one can use the 1 month Treasury choice in the "Mixed Portfolio" section which is in the range of online bank rates.