On the 18X, you have to poke the shadow register ($AE) to set direction and then control the pins by poking PORTB SFR ( $06 ).
Details and examples - <A href='http://www.rev-ed.co.uk/picaxe/forum/Topic.asp?topic_id=5857&forum_id=29&Topic_Title=Bi%252DDirectional%2BI%252FO%2Bon%2BPICAXE%252D18X&forum_title=No+new+posts+please%21+21' Target=_Blank>External Web Link</a>