Can document colours be saved as a colour palette?

[photoken]

I've used the colour picker to save 8 colours from an image as a list in the Document Color List:

document colours.png

I can save that Document Color List as a preset, but I'd like to have those colours as a colour palette. Is there any way to do that?

What I'm trying to accomplish is to reduce the colours in an image to 8 colours, but the available palettes in the Reduce Color dialog don't work very well for what I'm trying to accomplish. If I could save the Document Color List as a PL colour palette (.pal) file, the I could load it into the Reduce Color dialog.