i just tested this command and it worked fine
{.copy|E:\test è loooooong.veeeery|C:\test è loooooong.veeeery.}
the final name was just the same, no truncation.
Also, consider that if you don't need to change the destination name, this form would work as well (same effect)
{.copy|E:\test è loooooong.veeeery|C:\.}
So, about your problem, i can think only of these
1) you are using a non-turkish Windows XP, this mean that the file name is actually unicode (being not local codepage) and HFS is known to not support such situation.
2) you are running {.copy.} in a place where using %item-resource% or %item-name% are truncated.
both my guessings mean the problem is not in the {.copy.} itself.
let me know