NI 6713 digitalio object direction issue

I am using a ni 6713 board w/ matlab 2010 (and 2007b, actually). Matlab help claims that setting a dio line's direction to "out" results in bidirectionality (can be used as in or out). Yet i do not get this to happen. Getvalue retrieves the correct value only if i set the line to in. But i need bidirectinality. Or if i could set some lines in and some out that would work. But matlab says that all lines on this "port" (its a board!?) must be the same direction. Any ideas?