Elastic-Plastic analysis

I am trying to run an elastic-plastic analysis on a very simple model, but I am stuck and will really appreciate if someone will tell me where I got lost.

My model is a pipe, 2m long along the X-axis, 500 mm ID and 3 mm thick. Both ends are constrained agaist Y and Z translation and one end agaist X translation. The loading is internal pressure and the (pressure x area) force in the X-direction. The model is meshed with fairly coarse terahedrons.

My comm file is mostly a rework from Claus Anderson's plasticity tutorial.

With pressure loading only, the analysis coverges in less than 15 itterations and the radial displacements are of the right order.

Loading the model with FX, with or without pressure, requires nearly 50 itterations on the first instance step and the output is utter nonsense.

I am using S-M 2013.2.

I attach my comm file and will really appreciate any held or comments or suggestions.

Thanks in advance