Do you intend to SEND email from your home set up, or ONLY receive?
If you plan to send mail, stop there - it will not work with any amount of reliability.
If you are still reading, you will need to use external DNS - how you will convey the IP address from dDNS to your DNS provider is unknown to me.
So, my suggestion is to not even try this. The only situation where you COULD possibly make this work would be if your provider does all of the following - which most will not do for residential customers.
- Give you a Static IP
- Provide reverse DNS for the IP
- Allow common mail ports to be opened
Otherwise you are very unlikely to be successful.