[Greasemonkey] Character encoding issues with GM_setValue

[Mark Pilgrim]

One of the scripts I'm working on downloads RSS/Atom feeds and caches
them with GM_setValue.  Downloading them works OK (i.e. parsing the
responseText with DOMParser produces the correct DOM tree of the
feed), but when I read them back with GM_getValue I get
"non-wellformed XML" errors.  I suspect that the issue is one of
character encoding; the values stored in the Firefox preferences
database don't handle character encoding properly.  Is this a known
issue, and if so, is it fixable within GM or is there a workaround I
could try?

I get the same results storing things like document.title with
GM_setValue; if the title contains high-bit characters (example:
http://tbray.org/ongoing/ ) then the value gets munged when it's
stored.  about:config shows the raw value as terminating at the first
high-bit character.

-- 
Cheers,
-Mark