Keynote users: Creating a Master Slide from an existing slide ?

[tuqqer]

Sometimes, I create a great-looking slide that has everything in the right place, and I know I'll want to use it as a Master Slide, so that I can apply it to other slides that I create.

Is there any way to turn a slide into a Master Slide? If not, is there a way to at least easily add the elements and positions in that slide to a new Master Slide?

Currently, if I try to copy and paste elements (Text boxes, images, etc) into a new Master slide, nothing occurs.

Any ideas?

(using Keynote 3.0.2)