you really should re-generate your certs with better common-names (better in the eyes of openvpn). With that said, here you go:
OpenVPN manual wrote--no-name-remapping
Allow Common Name, X509 Subject, and username strings to include any printable character including space, but excluding control characters such as tab, newline, and carriage-return.
By default, OpenVPN will remap any character other than alphanumeric, underbar ('_'), dash ('-'), dot ('.'), and slash ('/') to underbar ('_'). The X509 Subject string as returned by the tls_id environmental variable, can additionally contain colon (':') or equal ('=').
While name remapping is performed for security reasons to reduce the possibility of introducing string expansion security vulnerabilities in user-defined authentication scripts, this option is provided for those cases where it is desirable to disable the remapping feature. Don't use this option unless you know what you are doing!
