OK, I took another pass at this. I can save bit depth and channels all right, but I can't seem to save sampling rate as a preset. Maybe I'm overlooking a step, but the whole procedure seems counterintuitive.
I'll report back if I discover anything else. I tend to do conversions as a batch process; I don't know if that makes any difference or not.
I don't want to read the manual either, but it isn't my problem, is it?
To create a preset, first select the setting you want, then enter the name of the preset in the "Preset" box, then choose "+". Also check into "Options | File Formats", "Default Save Format".