What is the range of Defensive Throw?

Defensive Throw (Complete Warrior p97):

If the opponent you have chosen to use your Dodge feat against attacks you and misses, you can make an immediate trip attack against that opponent. This attempt counts against your allowed attacks of opportunity in the round.

This does not mention any range, but the name and the prerequisite (IUS) implies unarmed reach.

Can I use my Guisarme against an enemy further away?