Did you find the IRC box? You have to enter the life and then I think there is a check box to take the $5,000.
Input is a series of entries starting at the top of the form and going to the bottom and when all are in the right sequence the system calculates.
(they could make this easier to find.)
As itonewbie indicated, if the rental does NOT rise to the level of a "Trade or Business", the "startup expenses" are not allowed. I would think most costs incurred before if was available for rent would be added to the Basis of the property for depreciation.