How do you complete a w-9 for income being paid to a Roth IRA

[Eric E.]

We completed a profitable transaction within a revocable trust. The trust is held by my Roth IRA. The payor insists on a w-9 form. The trust does have an EIN, but how do we fill out the w-9 so that the IRS does not think the profit is taxable? Do we put a code in Box 4 ? Or is there another way to complete the w-9? Instructions on what code to use in Box 4 are not really clear to me.