CodeWarrior v10.5 includes CodeWarrior Classic Project Importer for CW DSC v8.3 projects, but CW v10.4 does not.
CodeWarrior v10.5 can be downloaded from:
http://tinyurl.com/6jo5tge
If you would use CW10.4, the solution is user needs to create a new bareboard project in CW10.4 and then add/copy all your source files to the new project. For a project with PE, user also have to add the PE component manually.
Below is an application not for how to do this:
http://cache.freescale.com/files/soft_dev_tools/doc/app_note/AN4727.pdf