When the cell server is not registerred in DNS, the standard form of omnigencert.pl may fail to create all needed cell server server and client certificate files :
perl omnigencert.pl -server_id <servername> -user_id hpdp -store_password <password>
If files like ca.truststore, server.truststore are missing in certificates directory, it may help to use an extended form of the command :
perl omnigencert.pl -server_id <servername> -server_san dns:<servername> -user_id hpdp -store_password <password>
PS: make sure you use correct store password, as defined in AppServer config files.