if you just want to check if it's displayed at run time, try performing a .GetAllItems?, (can't remeber the exact method) on the list box, assign the output to a string, then perform an VBScript 'Instr' on it to see if your specific item is in there.
There is no such kind of method to get all the items in a list box for a web application. We can only get a particular item by .GetItem(Index)method. Actually there is one for windows appl which is .GetContent to get all the items in a combo box.
So if anyone knows any solution please let me know..