From the "Copy" menu (in Edit Style) I think you have to press F4 to select the internal styles, choose one where you want to copy (or or some parts of it as fills, intro, etc.) and ... is already done!
Looking for something like you said I still not make a copy from style to style.In Audya manual it do not show any topic about the copy? I can see a copy function in the menu but it is not a copy style.