Implementation of Jaumann stress rate into FEM program

Hi,

 Im building hypoplastic constitutive model into FLAC3D.

 My formulation is by the Jaumann stress rate.

In order to implement the model into the FEM does I need to change the increment stress as followed by the Jaumann stress rate definition as

dsigma=jaumann+W*sigma-sigma*W

where W is the skrew-symmetric part of the velocity gradient.

Or should I use the Jaumann stress rate as the incremental stress.

Thanks,

DoKo.