uid & gid problem restoring ubuntu made backup to new squeeze install

["Juan R. de Silva" <juan.r.d.silva@gmail.com>]

I'm in the process of moving from Ubuntu to Debian. I've installed 
squeeze and want to restore some of 2 users home files and directories 
from a backup made in Ubuntu. There are also some files from /etc needed 
to be restored.

I preserved the user names for both of users in a new squeeze 
installation but UID and GID are different. So, by simply using 'cp -
a' (or rsync) I would run into problem of their mismatch.

Is there a simple and quick way to resolve it or I'll have to go trough 
this mess manually one step at a time?

I know I could change UID and GID in Debian to Ubuntu values but I am 
quite reluctant to go this way.

Thank you.