I think I did it!!!
The charset problems should be gone as of beta 2 ... I've learned much this day

Please report if all is working now...
I've already tested espaniol wiki and it is working fine with forum set to "ISO-8859-1"
*HAPPY*
I'm converting the wiki content to the forum charset now.
... sure it is better not to convert it, so if possible set the forum to UTF-8