Arch Linux

I use putty to access an arch server through ssh. I regularly use screen to manage several virtual terminals through the ssh connection. Whenever I use the pacman-screen-putty combo to update or install a package, the progressbar during downloads does not work. On an update, instead of the progress meter moving to the next position, a newline is appended to the current line and the entire progress line is reprinted to the screen like this:

%<-------- begin screendump
~ # sudo pacman -S zope

Targets: zope-2.7.4-1

Total Package Size: 4.8 MB

Proceed with upgrade? [Y/n]

:: Retrieving packages from extra...
zope-2.7.4-1 [#### ] 29% 1472K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 30% 1483K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 30% 1494K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 30% 1506K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 30% 1516K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 30% 1528K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 31% 1539K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 31% 1550K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 31% 1562K 0.0K/s 00:00: zope-2.7.4-1 [#### ] 31% 1573K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 32% 1584K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 32% 1595K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 32% 1607K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 32% 1618K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 32% 1628K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 33% 1640K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 33% 1651K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 33% 1662K 0.0K/s 00:00: zope-2.7.4-1 [##### ] 33% 1674K 0.0K/s 00:00:00

%< -----------end screen dump

I have tried various combinations:
* turning on/off ILoveCandy
* running through screen on the desktop directly
* running through putty w/o screen

the only combo that reproduces this is the one in the title: pacman->screen->putty.

I will look through the pacman progressbar code in my rare^H^H^H^Hspare time.