it will mount it to a new folder in /Volumes ... which means the CD drive link in your wineprefix dosdevices is probably wrong... this works ok with some installs and not others... its easiest on installs that ask you to insert the disc and let you locate it if not found... ones that are hard coded to be in the same exact spot.... well sometimes I've had to mount the disc by hand in terminal with the same exact mount name. see if you can run winecfg while its asking for the other disc and make sure the same exact drive letter you were using before is linked to the new CD correctly... or you can do it manually with symlinks in the dosdevices folder. May not help, but worth a look.
