You post Banking menu > Enter Credit Card Charge for that Employee name as "purchased from" and on the expenses tab, you list Other Current Asset = loaned to employee. No details, never hits your P&L, no real payee, etc.
Now you will set up a Payroll Deduction item from Net pay, as a wage garnishment. Instead of linking this to a liability, you link it to that Other Current Asset account as an employee loan or advance Repayment. It reduces their takehome, but does not affect any other tax computations.
You deduct it until the loan is Paid in full.