Something converting <br /> to <br>

I am using WP 2.0.5

I initially set up this blog a few weeks ago and recently switched the default theme to one based on a theme called Solitude.

I am continuing to modify the theme and CSS Style so that the blog looks the way I want.

I am also running the generated pages against the W3C validation engine… I have got it down to only 3 errors but I am having trouble figuring out how to get rid of them.

One issue is that I have a couple of <br> tags that keep showing up… Under XHTML, of course, it should be
and, in the particular PHP code file (sidebar.php), the HTML does have
… And if I look at the source for a particular page in the browser (say FireFox), I see the
with the slash… But if I ask FireFox to show me the “Generated Source”, I find that the slash has been removed and I am back to the old HTML 4 <br>… And this, of course, will not validate as XHTML.

If someone can tell me where or how to stop WP from switching the
to <br>, I would appreciate it.

TIA,

–Doug
Salem Design