In-series plugin: getting just a URL, docs inconsistent

I’ve installed skippy’s In-Series 2.0 plugin and I’ve edited the index.php in our theme to use it. It’s just what we need!

QUESTION #1: I’d like to call next_in_series() and previous_in_series() from header.php and have them return only the permalink URL for the next or previous article. (I want to generate “next” and “prev” link headers.) I don’t want the function to generate an HTML tag; I just want it to return a URL. Example:

$nextlink = next_in_series(...);

and $nextlink would contain exactly (for instance) http://myblogsite.com/some-article-23. I’m not much of a PHP hacker; how can I get that result?

QUESTION #2: The documentation for In-Series is inconsistent. I tried to mail a bug report to skippy, but my email bounced back with an error saying that it was spam. I also don’t see any recent replies from Skippy on his In-Series page http://www.skippy.net/blog/2005/05/26/plugin-in-series/. Skippy, are you still around?

Here’s the problem: his blog page lists four functions, previous_in_series(), next_in_series(), all_in_series(), and series_table_of_contents(). But the README file included with the plugin, in-series.txt also mentions the all_series() function. I guess it’s a supported part of In-Series?

I’d like to suggest that Skippy add all_series() to his blog. Or (better), he could put the whole in-series.txt file online and link to it from his blog; it’s much more complete than the description in the blog.

Thanks.