Ha, I happened to know that. It is kind of tricky. The correct way to save your presets is as follows:
1: Under the IR LOARDER section, Click "SAVE" button, not the PRESET, that's where you will get the problem.
2: In the pop-out window, make sure you are under "Torpedo" section, then choose the slot you want, click it, then rename "Preset name" column.
3: Click "SAVE" in the right bottom corner.
That's the process that I was trying ......