Index: wp-admin/includes/file.php
===================================================================
--- wp-admin/includes/file.php	(revision 14081)
+++ wp-admin/includes/file.php	(working copy)
@@ -34,7 +34,7 @@
 	'audio.php' => __('Audio Attachment Template'),
 	'application.php' => __('Application Attachment Template'),
 	'my-hacks.php' => __( 'my-hacks.php (legacy hacks support)' ),
-	'.htaccess' => __( '.htaccess (for rewrite rules )' ),
+	ACCESS_FILE_NAME => __( '.htaccess (for rewrite rules )' ),
 	// Deprecated files
 	'wp-layout.css' => __( 'Stylesheet' ), 'wp-comments.php' => __( 'Comments Template' ), 'wp-comments-popup.php' => __( 'Popup Comments Template' ));
 
@@ -92,7 +92,7 @@
  * @return unknown
  */
 function get_real_file_to_edit( $file ) {
-	if ('index.php' == $file || '.htaccess' == $file ) {
+	if ('index.php' == $file || ACCESS_FILE_NAME == $file ) {
 		$real_file = get_home_path() . $file;
 	} else {
 		$real_file = WP_CONTENT_DIR . $file;
Index: wp-admin/includes/misc.php
===================================================================
--- wp-admin/includes/misc.php	(revision 14081)
+++ wp-admin/includes/misc.php	(working copy)
@@ -126,7 +126,7 @@
 	global $wp_rewrite;
 
 	$home_path = get_home_path();
-	$htaccess_file = $home_path.'.htaccess';
+	$htaccess_file = $home_path . ACCESS_FILE_NAME;
 
 	// If the file doesn't already exist check for write access to the directory and whether we have some rules.
 	// else check for write access to the file.
Index: wp-admin/options-permalink.php
===================================================================
--- wp-admin/options-permalink.php	(revision 14081)
+++ wp-admin/options-permalink.php	(working copy)
@@ -116,7 +116,8 @@
 	else
 		$writable = false;
 } else {
-	if ( ( ! file_exists($home_path . '.htaccess') && is_writable($home_path) ) || is_writable($home_path . '.htaccess') )
+	$htaccess_file = $home_path . ACCESS_FILE_NAME;
+	if ( ( ! file_exists($htaccess_file) && is_writable($home_path) ) || is_writable($htaccess_file) )
 		$writable = true;
 	else
 		$writable = false;
Index: wp-includes/default-constants.php
===================================================================
--- wp-includes/default-constants.php	(revision 14081)
+++ wp-includes/default-constants.php	(working copy)
@@ -56,6 +56,10 @@
 	if ( !defined('WP_CACHE') )
 		define('WP_CACHE', false);
 
+	// Add define('ACCESS_FILE_NAME', '.your_file_name'); to use a custom AccessFileName
+	if ( !defined('ACCESS_FILE_NAME') )
+		define('ACCESS_FILE_NAME', '.htaccess');
+
 	/**
 	 * Private
 	 */