You can manually adjust the foreign SE tax-related business income using negative values losses under:
Other tax situations -> Business Taxes -> SE tax
At the same time, mind that IRS will require you to have a 'foreign certificate of coverage' for such SE tax payment avoidance + leave notes under your SE form (wherever you find appropriate in TurboTax).
I don't think reporting losses in such a way is how it is supposed to be done officially, but this is the only technical way if you still want to e-file using the free TurboTax version.
