questions on apt-pinning

[Bob <spam@homeurl.co.uk>]

Hi, I just tried Lenny and MergeFB is busted for that combination of 
xserver-xorg-core and xserver-xorg-video-ati, for the moment the fix is 
install xserver-xorg-video-ati from experimental, so I have to delve in 
the world of apt-pinning.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=420628

If I install a package from experimental or sid, is there any way I can 
track it's progress down the tree? that is to say, in some months time, 
when a fix or feature has trickled down to Lenny, I don't necessarily 
want to be running whatever even newer version is in experimental or 
sid, which may well have problems of it's own.  Failing that how do you 
downgrade a package from the one in sid to the one in testing?

In the /etc/apt/preferences file, is there any way of pining to a 
release rather than to stable or testing?  I've got used to using the 
release codename in my sources.list so that I don't upgrade until I 
change the link in sources.list and issue an apt-get dist-upgrade.
It seems in the preferences file an entry like

Package: *
Pin: release a=etch
Pin-Priority: 700

doesn't work and you have to use a line like,
Pin: release a=stable
Is there a way round this inconsistency?

Thanks for your time and any help.

B