Setting pressure point constraint in closed fluid mechanics problem

Hi

My problem involves a closed sphere filled with magnetic fluid put near a rectangular bar magnet. Physically when this is done there is a pressure build up in the fluid because of the magnetic body force generated and there is no steady state flow.

The magnetic fluid magnetization is kept simple and is described by the linear relation M=Xi *H in the different directions. The volume body force density is given as follows
Fx=Mx*d(Hx,x)+My*d(Hx,y)+Mz*d(Hx,z)
Fy=Mx*d(Hy,x)+My*d(Hy,y)+Mz*d(Hy,z)
Fz=Mx*d(Hz,x)+My*d(Hz,y)+Mz*d(Hz,z)

The boundary condition on the fluid is no-slip and continuity for the normal magnetic flux density.
If I specify a non-correct pressure then COMSOL gives me a static result of positive flow when this is not physically correct. The problem I am having is I dont know the pressure point constraint that I need to specify so that the problem converges. I would like for the problem to solve the pressure automatically.

I have attached the problem. Any help on this will greatly help me and people with similar problems in closed fluid mechanics problems
Thanks
Shahriar