panel does not pick up preseeded locale/translation

Natty.
Ubiquity version 2.6.10

/usr/lib/ubiquity/panel does not pick up preseeded locale (zh_CN).

So, default panel indicator applets (network-manager-gnome, indicator-sound, and indicator-session) are all in English after installation and before oem-config runs/completes. After oem-config completes, the applets are all in the right locale/translation.

(ibus applet IS in zh_CN, I think because it starts later and picks up the locale)

In another tty after install and before moving along in oem-config:
LANGUAGE=zh_CN
locale shows all key values in zh_CN
language-pack-zh-hans (and depends) is installed (I install this at image build time)

And, as verification that the translation chain is intact for an indicator app, I can display a zh_CN translation from indicator-sound at the command line in tty 5 after install and before oem-config with:
gettext -s -d indicator-sound "Sound Preferences..."
(it displays zh_CN translation from /usr/share/locale-langpack/LC_MESSAGES/indicator-sound.mo)