If you select games where the 0-0 FT is 15.0 or greater, then back the FT for 2 units and lay the HT 0-0 so that the liability is more than covered by the profit on the FT bet.
The majority of these will produce a profit at HT, but when 0-0 at HT, you can either green up on the FT bet, for a loss overall, or risk waiting about 15 min of the second half, or until you can trade out for 0 P/L.
You need to research the relative amounts for each bet, depending on the prices available. If you put more on the FT bet, thus reducing your potential profit, it may even be possible to trade out at HT, for 0 P/L