Anisotropic plasticity and hyperelasticity in Abaqus

I am trying to model a polymer that has been processed in such a way that it has oriented (orthotropic) material properties and undergoes very high strains (>100%) before break.

My appropriate choice using Abaqus and avoiding writing a UMAT is to use a Neo-Hookean HYPERELASTIC component along with a standard Mises isotropic hardening PLASTIC component.  The POTENTIAL option is then used to apply the Hill yield criteria through the prescription of the 6 yield ratios.  I applied this material model to a simple plate and applied a uniaxial and biaxial stretch (two different load cases) in order to assess the material behaviour.  The job runs and completes without any trouble and there are no errors, the problem is that the results remain exactly the same (isotropic) regardless of how the stress ratios are adjusted.  

I then swapped the HYPERELASTIC component for a standard linear ELASTIC component with equivalent properties and the results are as I would expect; the stress in each direction changes accordingly if the stress ratios are adjusted.

Can anyone comment on the compatibility of HYPERELASTICITY and ANISOTROPIC PLASTICITY in Abaqus (they should be compatible) or why it isn't working for me?

Also, if I can't get it to work I will use the linear ELASTIC component to model a St. Venant Kirchoff type large-deformation material. Any concerns regarding that?

 Please let me know if the input file or any extra information would be helpful