Anvil and French accents on SMP Servers

What I expected to happen was... :

Well, I wish to rename a lighter, on a SMP server, using the anvil. I'm french, but I still use the english language in the options. So, when I rename the lighter with the "Prométhée" name, it should take the name "Prométhée", no ? But...

What actually happened was :

When I click on the right box to take my "Prométhée", its name is "Prom?th?e", where the "?" are in fact in white boxes. I made some tests, and especially with the "Prométhée" name, there is an other bug : when I take the right item, it's in my mouse, no problem there. But the left item stays there, but it is a ghost item : when I click it, it diseappears... I couldn't reproduce this second bug with an other name...

Steps to reproduce :

• Take and anvil and put any item into, an axe for example.
• Rename it using accents, or use the "Prométhée" name if you want to experiment the second bug.
• Take the item on the right : you can now see its name. You can do the same thing with the second bug.

Thanks for watching.