Index: kernel/utility/event.php
===================================================================
--- kernel/utility/event.php	(revision 15331)
+++ kernel/utility/event.php	(working copy)
@@ -264,11 +264,17 @@
 		 * Allows to merge passed redirect params hash with existing ones
 		 *
 		 * @param Array $params
+		 * @param bool $append
 		 * @access public
 		 */
-		function setRedirectParams($params)
+		public function setRedirectParams($params, $append = true)
 		{
-			$this->redirect_params = array_merge_recursive2($this->redirect_params, $params);
+			if ( $append ) {
+				// append new parameters to parameters set before
+				$params = array_merge_recursive2($this->redirect_params, $params);
+			}
+
+			$this->redirect_params = $params;
 		}
 
 		/**
Index: units/helpers/mod_rewrite_helper.php
===================================================================
--- units/helpers/mod_rewrite_helper.php	(revision 15331)
+++ units/helpers/mod_rewrite_helper.php	(working copy)
@@ -89,20 +89,8 @@
 			$url = $this->HTTPQuery->Get('_mod_rw_url_');
 
 			if ($url) {
-				foreach ($this->_urlEndings as $url_ending) {
-					if (substr($url, strlen($url) - strlen($url_ending)) == $url_ending) {
-						$url = substr($url, 0, strlen($url) - strlen($url_ending));
-						$default_ending = $this->Application->ConfigValue('ModRewriteUrlEnding');
-
-						// user manually typed url with different url ending -> redirect to same url with default url ending
-						if (($url_ending != $default_ending) && $this->Application->ConfigValue('ForceModRewriteUrlEnding')) {
-							$target_url = $this->Application->BaseURL() . $url . $default_ending;
-							$this->Application->Redirect('external:' . $target_url, Array ('response_code' => 301));
-						}
-
-						break;
-					}
-				}
+				$this->_redirectToDefaultUrlEnding($url);
+				$url = $this->_removeUrlEnding($url);
 			}
 
 			$restored = false;
@@ -141,6 +129,68 @@
 			$this->HTTPQuery->finalizeParsing($passed);
 		}
 
+		/**
+		 * Detects url ending of given url
+		 *
+		 * @param string $url
+		 * @return string
+		 * @access protected
+		 */
+		protected function _findUrlEnding($url)
+		{
+			if ( !$url ) {
+				return '';
+			}
+
+			foreach ($this->_urlEndings as $url_ending) {
+				if ( mb_substr($url, mb_strlen($url) - mb_strlen($url_ending)) == $url_ending ) {
+					return $url_ending;
+				}
+			}
+
+			return '';
+		}
+
+		/**
+		 * Removes url ending from url
+		 *
+		 * @param string $url
+		 * @return string
+		 * @access protected
+		 */
+		protected function _removeUrlEnding($url)
+		{
+			$url_ending = $this->_findUrlEnding($url);
+
+			if ( !$url_ending ) {
+				return $url;
+			}
+
+			return mb_substr($url, 0, mb_strlen($url) - mb_strlen($url_ending));
+		}
+
+		/**
+		 * Redirects user to page with default url ending, where needed
+		 *
+		 * @param string $url
+		 * @return void
+		 * @access protected
+		 */
+		protected function _redirectToDefaultUrlEnding($url)
+		{
+			$default_ending = $this->Application->ConfigValue('ModRewriteUrlEnding');
+
+			if ( $this->_findUrlEnding($url) == $default_ending || !$this->Application->ConfigValue('ForceModRewriteUrlEnding') ) {
+				return;
+			}
+
+			// user manually typed url with different url ending -> redirect to same url with default url ending
+			$target_url = $this->Application->BaseURL() . $this->_removeUrlEnding($url) . $default_ending;
+
+			trigger_error('Mod-rewrite url "<strong>' . $_SERVER['REQUEST_URI'] . '</strong>" without "<strong>' . $default_ending . '</strong>" line ending used', E_USER_NOTICE);
+			$this->Application->Redirect('external:' . $target_url, Array ('response_code' => 301));
+		}
+
 		function _getCachedUrl($url)
 		{
 			if (!$url) {
@@ -224,11 +274,36 @@
 			$this->Conn->doInsert($fields_hash, TABLE_PREFIX . 'CachedUrls');
 		}
 
-		function parseRewriteURL($url)
+		function parseRewriteURL($string, $pass_name = 'pass')
 		{
-			$vars = Array ('pass' => Array ('m'));
-			$url_parts = $url ? explode('/', trim(mb_strtolower($url, 'UTF-8'), '/')) : Array ();
+			// external url (could be back this website as well)
+			if ( preg_match('/external:(.*)/', $string, $regs) ) {
+				$string = $regs[1];
+			}
 
+			$vars = Array ($pass_name => Array ('m'));
+			$url_components = parse_url($string);
+
+			if ( isset($url_components['query']) ) {
+				parse_str($url_components['query'], $vars);
+			}
+
+			if ( isset($url_components['path']) ) {
+				if ( BASE_PATH ) {
+					$string = preg_replace('/^' . preg_quote(BASE_PATH, '/') . '/', '', $url_components['path'], 1);
+				}
+				else {
+					$string = $url_components['path'];
+				}
+
+				$string = $this->_removeUrlEnding(trim($string, '/'));
+			}
+			else {
+				$string = '';
+			}
+
+			$url_parts = $string ? explode('/', mb_strtolower($string, 'UTF-8')) : Array ();
+
 			$this->_partsToParse = $url_parts;
 
 			if ( ($this->HTTPQuery->Get('rewrite') == 'on') || !$url_parts ) {
Index: units/helpers/user_helper.php
===================================================================
--- units/helpers/user_helper.php	(revision 15331)
+++ units/helpers/user_helper.php	(working copy)
@@ -319,10 +319,40 @@
 				}
 			}
 
+            // set language for Admin Console & Front-End with disabled Mod-Rewrite
 			$this->event->SetRedirectParam('m_lang', $language_id); // data
 			$this->Application->Session->SetField('Language', $language_id); // interface
+
+            // set language for Front-End with enabled Mod-Rewrite
+            if ( MOD_REWRITE ) {
+                $this->_injectLanguageIntoUrl($language_id);
+            }
 		}
 
+        /**
+         * Inject language into whatever page user wants to go after login
+         *
+         * @param int $language_id
+         * @return void
+         * @access protected
+         */
+        protected function _injectLanguageIntoUrl($language_id)
+        {
+            $mod_rewrite_helper =& $this->Application->recallObject('ModRewriteHelper');
+            /* @var $mod_rewrite_helper kModRewriteHelper */
+
+            $url = $this->Application->HREF($this->event->redirect, '', $this->event->redirect_params, $this->event->redirect_script);
+            $vars = $mod_rewrite_helper->parseRewriteUrl($url, 'pass');
+
+            $vars['pass'] = implode(',', $vars['pass']);
+            $vars['m_lang'] = $language_id;
+            $template = $vars['t'];
+            unset($vars['is_virtual'], $vars['t']);
+
+            $this->event->redirect = $template;
+            $this->event->setRedirectParams($vars, false);
+        }
+
 		/**
 		 * Checks that user is allowed to use super admin mode
 		 *