I took the RC2 mentionned above and I went and replaced the
message.php file with the one from the original numinu and I got the Vcard to work.
You can see it in action
here.
But in Firebug console, there are some javasript errors though but that has nothing to do with that switch I think.
EDIT: the VCard will work only if you don't have any mootools stuff on the same page as the forum.
I had to disable a mootools module I had in order to avoid conflicts between the two.
But it works on the
test site , the VCard pop up and everything.