How to backup preferences (customized toolbar, highlighting, ...) in UEX?

Looks like UEX configuration files on my Ubuntu 8.04 are kept in /home/<username>/.idm/uex. The files you are interested in are most likely uex.conf and uex.conf_vol -- both are regular text files structured very similar to Windows INI files. However, some of the data looks like it is stored as hexadecimal representation of binary values. Therefore, I wouldn't recommend editing the file manually.