Arbitrary value to filekey should be fine--this is just the primary key that uniquely identifies the record.
As far as using the component in your package, this should be fine, as long as it is marked for Installation (with an 'InstallMode' of 1) or the component is marked for Uninstallation (with an 'InstallMode' of 2).
Try generating a logfile, and link it on this thread--I'd like to see what's taking place, since it seems to me as though it should work fine:
HOWTO: Logging an MSI Installation:
http://support.installshield.com/kb/view.asp?articleid=Q104807