[ShiningArcanine]

I wrote my own version of this:

<if condition="$vboptions[externalrss]">
<link href="$vboptions[bburl]/external.php?type=rss2" rel="alternate" type="application/rss+xml" title="<phrase 1="$vboptions[hometitle]">$vbphrase[x_dash_latest_posts]</phrase>" />
<if condition="$foruminfo[forumid]">
<link href="$vboptions[bburl]/external.php?type=rss2&amp;forumids=$foruminfo[forumid]" rel="alternate" type="application/rss+xml" title="<phrase 1="$vboptions[hometitle]" 2="$foruminfo[title]">$vbphrase[x_dash_latest_posts_in_y]</phrase>" />
</if>
</if>

It uses the phrase system and the settings in vBulletin options. Anyone who wants to use this without modifying it would want to create two custom phrases. One would be named: x_dash_latest_posts and have this content:

{1} - Latest Posts

The other would be named x_dash_latest_posts_in_y and have this content:

{1} - Latest Posts in {2}

I hope that helps someone