Wait just a second, I think your making this more complicated than it needs to be.
Create a startup script for Creo that selects a different location for the cache. Have the user register the server. Open the files in Creo, and then Save a backup to a folder. Exit Creo Then open Creo the way you normally do and browse to the folder. \
Your startup script would need a line something like this: set PTC_WF_ROOT=%USERPROFILE%\pro\creo_2_home\cache\no_pdm_cache\PTC\ProENGINEER
Both startup scripts would need this line in them: tskill creoagent
This prevents the creoagent from informing Creo of the last registered server.