OpenVPN: certificates and AD Connector

1. According to the OpenVPN guide, I need to setup the ClearOS Certificate Authority to issue certificates for the OpenVPN connections. However, I also plan to install a separate trusted cert (wildcard) that I've purchased from Comodo for use with the webconfig. Is this a supported configuration, to be running a separate SSL certificate for the webconfig and another with self-signed certs for OpenVPN?

2. I'm using ClearOS with the Active Directory connector so that I can use my AD users with ClearOS resources. In order to allow a user to access my ClearOS server via PPTP VPN, I have to add them to the pptp_plugin group in Active Directory. Is there a similar group I need to use to allow OpenVPN access? openvpn_plugin?