Tracking Basis for Solo 401k After Tax Contributions

I am a sole proprietor (Schedule C) who has a Solo 401k. 

I Solo 401k plan allows for after tax contributions, and in 2023 I want to take advantage of it.

 

I don't see a place with TurboTax that allows me to track and report basis (after tax contribs) for Solo 401k, similar to what is available in the IRA section.

I am very familiar with the IRA basis section and use it. Just don't know how to avail the same feature for the Solo 401k.

Please advise.