Vidalia ExitPolicy overwrite assistance?

["Richard Johnson" <rdump@xxxxxxxxx>]

I'm using tor 0.2.0.23-rc on a Mac OS 10.4 box, as installed and configured
with Vidalia, and wish to run a relay.

However, there are some networks which it would not be wise to have
reachable from my relay via tor, including most importantly my local /16
(while my netmask is /22 or /24).

Vidalia's GUI has checkboxes for groups of ports, but nothing for
specifying subnets.

I can edit /Users/rdump/.vidalia/torrc to put in the necessary ExitPolicy
stanzas, but Vidalia rewrites the entire file when I make unrelated changes
to the configuration, and thereby removes my ExitPolicy stanzas.

Short of firing up tor manually, can you suggest a workaround that will
preserve at least the critical 'reject XXX.YYY.0.0/16:*' stanza from this
example ExitPolicy line?

| ExitPolicy reject XXX.YYY.0.0/16,reject *:80,...



Richard