Not familiar with either but.
Is it registering? If not, port settings, Protocol (TCP / UDP), Passwords, Auth Names?
Are the Codecs the same? I'd always start with G711a/u and work from there.
Robert Wilensky:
We've all heard that a million monkeys banging on a million typewriters will eventually reproduce the entire works of Shakespeare. Now, thanks to the Internet, we know this is not true.