Ah, I figured it out. I took at look at pal.c and found examples via the default palettes, they are just simple arrays:
 const u16 palette_red[16] =
{
 0x0000,
 0x0002,
 0x0004,
 0x0006,
 0x0008,
 0x000A,
 0x000C,
 0x000E,
 0x000E,
 0x000E,
 0x000E,
 0x000E,
 0x000E,
 0x000E,
 0x000E,
 0x000E
};