curses: xterm vs. linux terminal

[Brian Alexander]

Hello;

Why is it that the curses special (alt) characters do not display on xterms?

Ex:

theScreenObj.box(curses.ACS_VLINE, curses.ACS_HLINE)
theScreenObj.refresh()

This code puts a box with graphical characters around the window when 
the terminal is of type linux. When the terminal is of type xterm, 
blanks appear where the line characters should be.

Is there anyway to fix this behaviour? I find it hard to believe an 
xterm does not support the drawing of these simple graphical characters.

Many thanks,

Brian.