I have them on the same machine. You have to have a separate installation directories and separate config.pro directories else it will over write the old ones even if you are doing a clean install.
Once that is done, should should be good. Just remember that you don't want to open and save any current - non test files and save them in Creo 2.0 because thing are not backwards compatible.
With those thing in mind, you could copy some test files to a new directory and work on them there so that if an assembly is called up in WF5, you don't get any issues with a part already being saved in C2.0.
Thanks, Dale