Index: src/core.js
===================================================================
--- src/core.js	(revision 3790)
+++ src/core.js	(working copy)
@@ -483,8 +483,23 @@
 					if ( elem.nodeType == 1 )
 						scripts = scripts.add( jQuery( "script", elem ).remove() );
 
+					// IE6 fails to copy the checked state over on appendChild type calls
+					if ( jQuery.browser.msie && jQuery.browser.version == "6.0" ) {
+						var c = jQuery(elem).find("input").andSelf().filter(":checkbox,:radio");
+						c.each(function () {
+							this.saveChecked = this.checked;
+						});
+					}
+
 					// Inject the elements into the document
 					callback.call( obj, elem );
+
+					// set the checked values in IE6 (from above)
+					if ( c )
+						c.each(function () {
+							if (this.saveChecked)
+								this.checked = true;
+						});
 				}
 			});