Hi,
This issue is probably resolved. Anyway, just in case someone else is facing this issue...
In CodeWarrior Classic (CW for MPC55xx/56xx v2.x) there is no option to generate a library project in a New project wizard.
I'd suggest creating a new application project for selected derivative and then go to project properties (Alt+F7) and change the EPPC Target settings - Project type to "Library" and adjust the output file name e.g. to "my_library_name.a":

With this change go back to the project and remove all unnecessary files (linker command file, startup, files etc...) and let just the source files with library functions. When you successfully build the project there is an .a file in your output directory.
Hope it helps.
Stan