Optimizing with a complex number

Hello again,
I am currently stuck with the optimizer. I made a forward model to give me the magnetic field, then using the optimizer, I am trying to get the resistivity of my model, by giving it the magnetic feild. The Resistivity is complex, and I can not get the optimizer to give me a complex value back. I found, and checked off, allow complex value output with real input, and split real and complex numbers. The issue is when the solver finishes, I just get my inital value (which is not the same as I used in the forward model) back. Is there something I could be missing here? The model works, and optimizes fine when I use a real resistivity.