Additional 401K contribution in paycheck tracking

I am looking at how to properly set up this in my payment reminder. My employer does and additional contribution to my 401K. This appear on my paycheck but it not a pretax deduction. I already have my employee contribution set up and linked to my 401k investing account in quicken. Aside from going in manually in quicken and adding that, is there a way to add it as part of the paycheck reminder so I do not have to. No matter what I do, it alters my net pay. Any suggestion will be helpful.