Ask your provider to send sip packets to 5080, instead of 5060.
Every good provider should allow you to select the port YOU want, and not THEY want.
If it will not help, then you need to make external profile listen to 5060, instead of 5080.
So, you will be sending and receiving sip messages between you and provider, using port 5060 (which is usually used only for your internal profile and your clients).
To change this, you need to modify conf/sip_profiles/external.xml
<param name="sip-port" value="5080"/> replace to "5060"
In this case, you will have to reconfigure internal profile to be on a different port, say 5062, and ask your clients to add :5062 to the sip server address when they configure their softphone/sip adapter.
Maybe another option would be to consider provider as one of your internal clients, and allow password-less communication from his IP, but this is way too crazy to consider as a good option.
Vitalie