Exchange global list

My company has a central store of contacts store within the public folders in exchange.
I am able, from within my outlook, to traverse the tree to the contacts folder,right click on the contact I want and choose to send a message to this person.
What I can’t do is access that central list when I open a new message and hit the ‘To’ button. I can only see my personal contacts, the list of users within the company and email groups setup in exchange.
This wouldn’t ordinarily be a problem as there is a workaround solution, but I’ve installed GFIfax software and can’t use the work around to send the fax from within outlook.
Can anyone tell me how to access the global contacts list from my address book in outlook ?