Sounds like to me Orstio doesn't want to have two code bases.
1.5 is a ways off yet.

I would stick with Joomla and even more of a reason to stay with Wolverine's bridge.

Might be having a issue finding your lang file.
File com_smf/smf.php uses english if it can't find the lang file to include so maybe you can hack a hard code to your lang file.

That code starts at about line 92 in the rc3 version of the bridge.

I had a similar issue with the "install" part of setup.
My setup uses PHP 5.04 and I ran into this same "include" issue with the installer and the script not being able to find a file in same dir as itself.

I worked around my issue by using this hack in the function.php file:

Not sure if this is a php bug but it is not the first time I have run into this with php 5.0

Hope this helps someone.