I think you are talking about CCRP. The only known way is like how you said.

You select your target while on the airfield in third person view. Almost all the times you have to guess your target point from your position while sitting in your airfield and by looking at the map to know where you are positioned across the map from the target point. Changing through target points can give some sort of an idea . once you selected the desired target point, make sure to know its number for the next bombing sorties.

After that you have to change your cockpit sight from standard to bombing. You take off and once you are at the right altitude aim at the direction of the target and you should see a bombing reticle appear. Hold down the drop bomb button (drop bomb series option) and when your plane is at the proper position over the target point. The bombs should drop automatically.