I'm not sure whether ABE supports lookahead expressions.
@Thrawn, AddressMatcher converts all valid (non-IP-subnet) syntaxes into regexp using "new RegExp(string);", so whatever regexp syntax is supported by the browser is therefore also supported by ABE.
*Always* check the changelogs BEFORE updating that important software!
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:26.0) Gecko/20100101 Firefox/26.0 SeaMonkey/2.23