Which column of this list box is the Bound column, or is this list box not bound? If EntryID is the bound column, all you need to do is set the list box equal to EntryID that you receive from the search form. If EntryID is not the bound column, then you will need to, with VBA, look at each entry in the listbox until you find the EntryID you are looking for, then set the list box equal to whatever the bound column is for the same row that you found the EntryID on.
If the EntryID is NOT the bound column, then my suggestion would be to use the SQL from the RowSource property to create a query, do a DLookup for the EntryID from this query and have the DLookup return the value for the Bound column, then set the ListBox equal to this returned value.
Hope this helps,