I've send you the fixed source back.

But for the record, in case somebody searches the forum for the solution:
To check the client certificate the SSL_verify_mode must *include* 0x01 and to force it to fail if no client cert it must include 0x02, which means together 0x03 (bitmasks).
The other problem was that the server checked the peer certificate on the listening socket and not on the socket connected to the client