[wp-hackers] Working $allowed_keys

[Kaf Oseo]

"Allowed keys" for orderby var really should include 'modified'. But
since it doesn't... Beside an edit to classes.php, can I override or
append to the $allowed_keys array under get_posts in WP_Query class?

I'm writing a how-to for a Page template that includes a feature for
selecting sort method: title, date and modified, and I'd like a way
for someone to accomplish the last without requiring an edit to the
core.

-Kaf