1st you need to set up 1 or more account codes
2nd creat a short code for the number ranges you wnat to pin protect ie 00N for international calls & tick the forced accunt code box
3rd creat a short code to set the pin, *99*N#, Number: N, Feature Set account code ( one of my custs uses the short code XXX to use 1st 3 digits dialed as code)
Now dial *99*<pin>#, wait for dial tone, Rest of number.
If speed dials have a matching entry in account codes then they can still be used as normal, the IPO will auto match the pin.