Impossible. The rationale is the mutual fund expense is intrinsic to the investment itself. IT's a cost of operting the "company" that you are investing in. Even though it is not the same, it is tantamount to reimbursing a participant who invests in IBM for the rent IBM paid on its real estate. I know it's a crazy analogy but it is spot on. You are investing a "business" that is in the business of investing money and one of the expenses of that business is to pay a fund manager.
Anything you do in this regard would be an employer contribution, and with it goes everything that applies to employer contributions (document provisions, testing, 415 limits, etc).
In other words, forgettaboutit!