upgrade to kde 4.5 from ubuntu-backports

Hi,
I would like to try to upgrade to kde 4.5 from the backport repositories, but I would like to know two things first:

1) how can I revert to 4.4 if things fail (there have been some errors been reported at the ppa launchpad)?
2) will there be problems with upgrading to 10.10 when I use the backport repositories?

Thanks in advance for any help!

Beware of it !

I tried (only for using a newer version of amarok), got a completely corrupted system
http://forum.kde.org/viewtopic.php?f=121&t=96487

Maybe it were my mistakes, please read it

mue.de

Since AlmaTlust's post is over a year old, I'm going to assume this issue has been resolved. Closed.