I could not have all the Free Domain Forwarding, Email Forwarding and Managed DNS service offered by Domain registrar to be activated and worked together on the same sub domain name
Limitation on the Free Add On service offered by PDR Domain Registrar
If you wish to set www.domain.com for A-record in Managed DNS feature, then you are NOT able to configure Domain Forwarding on the same sub domain www.domain.com, and vice versa. This is due to both function cannot be working at the same time for the same domain. If you would like to configure Domain forwarding for domain.com, you can only configure it under another sub domain, such as file.domain.com.
Alternatively, you may go for the Paid Managed DNS & Domain Forwarding service. Visit link below for the pricing: http://billing.netonboard.com/cart.php?gid=17
The same if you would to configure mail.domain.com for MX record, then mail.domain.com is NOT allowed to configure for Email forwarding, and vice versa.
Alternatively, you may gor for the Google Apps (free version). Visit link below for the pricing: http://billing.netonboard.com/cart.php?gid=22