You will have to contact an NXP FAE to get an NDA in place before they will release the specifications. If I may ask, what is your specifications?
JCOP 4.5 is the latest OS and has a lot of options.
One option is to use the JCOP OS and build SecureBox functions in native code that can be referenced from Javacard. This saves you time so you do not have to build your own OS