The fee is deductible only if the management company reports the payment of the fee as a distribution from your retirement account, essentially making the fee payment from money that is no longer retirement money.
If the payment of the fee is not reported on Form 1099-R as a distribution, it is not deductible on your tax return. The fee is essentially being paid with money that was never taxed and, since the fee payment has reduced the value of your account, never will be taxed, you don't get to deduct it.
