> I already have a VE with let us say a Debian template. I have applied
> various settings to it. Now suppose I want to change the OS template
> alone to Gentoo or to something else without losing my other settings?
> Can this be done?
 That would be a fairly deep magic if it would be possible,

technically you can do it this way: 
 unpack a template, then run

 diff -ruN /var/lib/vz/template/cache/unpacked-template
 /var/lib/vz/private/ve-with-your-changes > my-changes.diff

and then apply the diff to your re-created template, but this would only
work for very simple things, and things that are compatible between
different templates ( for examples, say you created /root/Dear.Diary, and
logged some personal notes there, then this 'change' would still apply to
your new system, but then, let's say you installed some binary apps, then
the diff prepared this way, wouldn't work that well anymore )

-- 
Key fingerprint = 40D0 9FFB 9939 7320 8294  05E0 BCC7 02C4 75CC 50D9
 Total Existance Failure