Need L+R flush in header option

When I compile my manuscript for preview or export, in the header I want to be able to put my last name flush left and the page number flush right.

How can I do that? I see only Left/Center/Right options in the Text Options, Page Header/Footer settings.

Thanks!

You can’t do this yet, I’m afraid. This will be available in 2.0, but for now if you need more control over headers and footers you should tweak them in a word processor.
All the best,
Keith