Social Security Taxes and Medicare Taxes withheld

In addition to my regular pay, my employer pays me sales commissions and reports it on a W-2 as a statutory employee.  Social security and Medicare taxes are withheld but no income taxes are withheld.   After reporting the commissions on schedule C and not having to file schedule SE,  it seems to me I should be entitled to deduct one-half the SS taxes withheld as a normal business would.  If my assumption is correct; how would I accomplish reporting it on Turbo Tax?