How can I disable the sim code?

Hello, I just got a 4S and a new micro-sim for it.

The micro-sim has a default pin code for activation"1234" which I have to enter every time the phone is turned on.

As I already have the auto-screen-lock code, I dont need the sim to be locked too.

I couldn't find any setting in the iPhone regarding the change or removal of a sim-code.

Is the only option to find another phone that accepts micro-sim and use it to disable the sim-code?