Deductions & credits

This is a Turbotax question (not a tax question), because IRS-Pub550 states that Traders still show transactions on Schedule D if they've not marked-to-market.  However, Turbotax won't let me declare home-office expenses on Schedule C, because it thinks I have no profits (whereas my profits are declared on Schedule D per Pub550 instructions, not under the Business Income/P&L). Pl advise how to get around this issue and show Home-Office expenses on Schedule C.