Commission as 401(k) Deferrrals

[Randy Watson]

Employees receive commission upon the sale of the employer's product. The commission is considered compensation for purposes of our 401(k) plan and deferrals are withheld from these amounts when they are paid. Sometimes employees terminate employment prior to the payment of the commission.

So, my question is do we withhold deferrals from commission checks paid after termination of employment? These individuals are no longer employees when the amounts are paid, so how can we contribute deferrals to the plan for non-employees? Alternatively, the commissions are technically earned while employed. Please help.