Read the rest – in archives and categories

Hi, I’ve set up a blog WP 1.5 that, for the most part works just fine https://www.ilfpost.org.

One major problem is that while I’ve successfully used the Read the rest link on the initial posts, if a viewer clicks on the archives or Posts by Authors link (categories) only a few lines of the article appear but nothing to enable the user to read more of the article. Clicking on the title of the article works, but that’s not really obvious to the reader.

Is there some way to cause a Read the Rest link to appear on the posts listed in the archives and categories?