I think that you can probably just use print to create your own customer header section rather than using the header and start_html methods from CGI. For example, something like the following untested code:

print '<header>';
print '<link rel="stylesheet" type="text/css" href="/styles/invertor.c
+ss">';
print '<link rel="stylesheet" type="text/css" href="/styles/ie1.css">.
+;
print '<!--[if lte IE 6]>';
print '<link rel="stylesheet" media="all" type="text/css"href="/styles
+/ie2.css" />';
print '<![endif]-->'
print '</header>';
[download]

From a technical standpoint, I believe this will work. From a code writing viewpoint, I can definitely understand why some may not want to do this. In any case, I do believe that this a work around.

Also, you could take this concept a step further to create a subroutine that takes the parameters (similar to the header and start_html methods of CGI) and returns HTML code that you could print.