I had the same issue with ebox 1.3 but never got meetings to work even with the ebox kernel. Now on 1.4 I have the same problem. Interestingly I have 3 ebox servers running at the moment - all say they are fully up to date.
2 of them, a web server and the asterisk/jabber server, are running with the 2.6.24-27-server kernel and the samba server is using the 2.6.24-26-ebox kernel - ironic that the one that really needs the ebox kernel is not using it and one that probably does not is using it! Or maybe the samba/PDC does need the ebox kernel and is smart enough to know it while asterisk also needs it but is not smart enough to realize.
I don't really understand why 3 up to date servers would be running different kernels though - admittedly the web server was installed on top of an existing lamp server but the other 2 both used the ebox iso yet one sticks with an ebox kernel and one does not.