[Wine] Proper way to backup Steam games incl. registry keys

[mogorva]

I've read the AppDb entry for the Steam client here (http://appdb.winehq.org/objectManager.php?sClass=version&iId=1554), there is a small section in it howto reinstall steam, but there is no mention of the registry keys under HKCU/Software/Valve and HKLM/Software/Valve.
Especially HKCU/Software/Valve seems to be important as it contains not only app specific settings but also some cd keys.

What do you guys think? Is it enough to back up only the games' data and let the steam client re-create the registry entries, or should I back up the registry entries as well?