Use RegressionGP class for Code Generation

From reading the documentation about Code generation for C/C++, I would think that I would be able to load a class RegressionGP that I previously saved, but when I try to do this, it does not work. I suspect it has to do with the fact that the RegressionGP class includes cell arrays, which from further reading has shown to be troublesome for Code generation. Is there a workaround for this issue?