I'm tired about the situation when I'm unable to use kopete messanger. Seems like kopete developers don't want to fix the well known bug with ICQ cyrillic encoding.
One of the well known solution provided by patch by Oleksandr Shneyder AKA nCryer. Source: patch.
I made some small modifications in this patch and wrote ebuild file for the last kopete version.

How to use it?
1) Download kopete-3.4.3-r1.ebuild and place it in kde-base/kopete directory in portage tree. I use /usr/local/portage/kde-base/kopete with PORTDIR_OVERLAY=/usr/local/portage option in /etc/make.conf file.
2) Download patch file kopete_enc.diff and place it in kde-base/kopete/files/ directory.
3) Re-emerge kopete: emerge kopete