[wp-hackers] Permalinks Update Hook

[Mr.Brown]

Hi all,
I'm developing a photo gallery plugin for WP and I would make it
compatible both with 1.5.X and 2.0.X version.

The problem I have is this:

1) if the user install the plugin while the main blog has permalinks
not active, the plugin works. In the same way: 2) if the user install
the plugin while the main blog has permalinks active, the plugin works
(the plugin setup check if permalinks are active and if they are, add
its rewrite rules to .htaccess)

The problem occurs with case 1): I've a blog with no permalinks, I
active the photo gallery plugin, later I active the permalinks on my
blog: the plugin does not work because the rewrite rules for the
plugin are not set.

I would try to hook when the user updates the Permalink Options, so I
can generate and add the plugin rules to htaccess, but I need to know
if there is a hook available when Permalink Options are updated,
compatible also with 1.5.X versions, or at least a workaround.

Thanks!
-- 
Mr.Brown