Hi Erza, I ran into this as well. Memory serves me right it is disabled by default, and you have to turn it on.
Look in the worlserver.conf file below the AUCTION HOUSE BOT SETTINGS there is options to enable this for buying and selling etc.. and what type of items to sell as well..
Hope this helps you
here is my settings
AuctionHouseBot.DEBUG = 0
AuctionHouseBot.DEBUG_FILTERS = 0
AuctionHouseBot.EnableSeller = 1
AuctionHouseBot.EnableBuyer = 1
AuctionHouseBot.EnableBuyerNeutral = 1
AuctionHouseBot.UseBuyPriceForSeller = 0
AuctionHouseBot.UseBuyPriceForBuyer = 0
AuctionHouseBot.Account = 0
AuctionHouseBot.GUID = 0
AuctionHouseBot.ItemsPerCycle = 8500
futher down....
AuctionHouseBot.VendorItems = 1
AuctionHouseBot.VendorTradeGoods = 1
AuctionHouseBot.LootItems = 1
AuctionHouseBot.LootTradeGoods = 1
AuctionHouseBot.OtherItems = 1
AuctionHouseBot.OtherTradeGoods = 1
AuctionHouseBot.No_Bind = 1
AuctionHouseBot.Bind_When_Picked_Up = 0
AuctionHouseBot.Bind_When_Equipped = 1
AuctionHouseBot.Bind_When_Use = 1