If you are not using chunks, you can do something like this
Code:
MakeDefaultPreset("-", 1);
MakePresetFromNamedParams("-3 dB", 1, kInGain, -3.00000);
MakePresetFromNamedParams("0 dB", 1, kInGain, 0.000000);
That will give you a default preset and two other ones.
The presets will not be loaded until the user selects them. If you want to make the default value of a control (i.e., the value it starts with when loading), you will want to set it when you initialize the parameter
Code:
GetParam(kInGain)->InitDouble("In Gain", 0.0, -60.0, 20.0, 0.1, "dB");
That would initialize the value to 0.0, regardless of any of the presets.