I dont know if this helps you but here is how I got UTF-8 to work across systems using both 5.8 and 5.6.1 (and had to use uxterm on the 5.6.1 to get xterm to display it correctly)

#!/usr/bin/perl -w
BEGIN{
     if ($] < 5.008){
     require utf8;
     utf8->import();
     }
}
if ($] >= 5.008){
binmode STDOUT, 'utf8';}
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Basically if perl version ($]) is below 5.8 is uses one method of setting UTF-8 and if its equal to 5.8 or above it sets UTF-8 another way. I don't know how proper this is, but I was getting all kinds of trash whenever I tried to display Unicode (ISO-10646) on older Red Hat 7.3 in Xterm. After about 2 days of surfing I came up with the combination of using that in the script and launching in uxterm...now Unicode calls display properly on both types of systems.