International calling and PRI (TON/NPI)

I’m running asterisk 1.4.22 and freepbx 2.8.

I have customers placing calls (inbound, to be handled by asterisk) over a legacy PRI. International calls inbound have the proper TON/NPI info set, but have the ‘011’ stripped. [Common problem, from what I read.]

I’m led to believe that to re-add the 011, zapata.conf should have this before the relevant channels:

internationalprefix=011

but it doesn’t appear to work, despite trying pridialplan=dynamic, local, unknown, etc., and restarting *.

Anyone else have this problem? I’m working around it at the moment by adding specific outbound trunk rules in FreePBX for known countries, but I’m worried that it will conflict (at some point) with national dialing.

Thanks,
Jeremy