How can I apply a surface preload on a composite CF sleeve for non linear quasi static analysis?

I am a graduate research engineer at McMaster involved in FEA durability sims of e-motors. Our team is developing a high-speed (22,000RPM) radial flux motor surface-mounted permanent magnet motor. We are using a Carbon fiber sleeve that is wrapped around the magnets. The CF sleeve is prestressed at around 5MPa and I would want to apply this as a preload. I created a PLOAD4 defining the pressure on sleeve surface and defined it in the PRETENSION of load step. As I started to run the analysis it threw an error stating that only a PTFORCE or PTADJST card can be used to define pretension. Can you please suggest me a way to apply a surface preload (2D shell) in hypermesh for optistruct solver? Any leads will be appreciated. 

If not, I was also thinking about two load steps with sequential loading. The first load step with the pre-stress + constraints and the second with centrifugal loading alone. But I am not quite sure if I have to use any specific cards for sequential loading. Please help.