I'm running on an up-to-date Ubuntu 9.10 (64bit) system.  I've built the latest from Gnome git master (as of Sun 24 Jan 2010) of these packages: libxml2 libsoup samba4 evolution-data-server evolution gtkhtml libgweather evolution-exchange evolution-mapi evolution-webcal openchange

When I open up a new email message in Evolution, and select HTML mode, then select some text in FireFox (3.5.7), use C-c to copy it, then use C-v to paste into my composer message, instead of getting the text I expect I just get:

[?]

It works fine if I copy from OO.o (all my formatting is even preserved!), from an xterm, etc.  It's only FireFox which is causing these problems (that I've seen so far).  It doesn't seem to matter what the FF text is: whether it's monospace or not, etc.  Cutting out of this editing box does work OK, though.

Also it works fine if I select from FF with the mouse, then paste into the composer window with mouse-2 (although of course any formatting is gone) rather than using C-c/C-v.