To see latin characters and accentuation, you need to set your script encoding to UCS-2 Little Endian or other types of encoding rather than the starting "Code Page Property". That's all very nice but every script tha does some call to GUI and use those characters need to be setted to this encoding manually.
Is there any way to configure Uniscite to choose your default encoding?
Personally I'd recommend switching to Notepad++, which is also based on SciTE, so will feel familiar, but has more features and a proper UI for settings.
If you want to stay with UniSciTE, my config file has the following settings, one of which is likely what you're looking for ...
# Internationalisation
# Japanese input code page 932 and ShiftJIS character set 128
#code.page=932
#character.set=128
# Unicode
#code.page=65001
code.page=0
#character.set=204
# Required for Unicode to work on GTK+:
#LC_CTYPE=en_US.UTF-8
#output.code.page=65001