Reset negative PDF


I am using RooFit to build a composite model and fit to binned data. Some of the components become negative during the fit and RooFit returns large value of -log(L) to move away from such a region. Another approach is to use EvalErrorWall(False) which, as I understand, accepts such regions given the total PDF is positive. Is there any way to tell RooFit, that whenever a component becomes negative return a very small number?