Great Ideas,

I created a custom pallet using XPal ( http://www.smokingun.co.uk/index/downloads ) as suggested above. I then added it to a blank page and saved as a template. The colours didn't save in the template. Ultimatly, I found it easiest to create a palet in XPal, imported it to my document. Then I created a number of squares in a second layer named colours (page and layer gallery, right click - add a layer, then closed eye of layer 1 / opened eye of colour layer). I coloured each square with a colour from my custom pallet (which included company colours as well as gradients of those colours).

I then closed the visability of the colour layer (closed eye in Page and Layer Gallery), and opened visability on the main Layer 1. I then saved this blank document as a template.

When I now open a new document, all the custom colours are available on the colour pallet. Almost forgot, before doing the procedure listed aboove, I did as Scotty suggested and turned off "delete unused colors" from the Options menu.

Thanks for all the great suggestions. As always, there is a solution with Xara.