asterisk users - Mar 2014 - externhost and reregister

externhost is monitoring for ip changes with an interval of 
externrefresh, so far so good.

Wouldnt it be handy if asterisk would do an sip reregister if it detects 
an ip change?
My SIP provider has sometimes very high intervals of 1 hour and if ip 
changes, the registration doesnt work until it expires or asterisk is 
restarted or sip reload.

Or just everyone uses fixed ip addresses?

For now, seem to have to use a script with sip reload.