Index: t3lib/class.t3lib_befunc.php
===================================================================
--- t3lib/class.t3lib_befunc.php	(Revision 7074)
+++ t3lib/class.t3lib_befunc.php	(Arbeitskopie)
@@ -2646,6 +2646,14 @@
 				// Add it:
 			$addGetVars .= $suffix;
 		}
+	
+		// check if we need to preview a mount point
+		$sys_page = t3lib_div::makeInstance('t3lib_pageSelect');
+		$sys_page->init(false);
+		if ($mountPointInfo = $sys_page->getMountPointInfo($id)) {
+			$id = $mountPointInfo['mount_pid'];
+			$addGetVars .= '&MP=' . $mountPointInfo['MPvar'];
+		}
 
 		$viewDomain = t3lib_BEfunc::getViewDomain($id, $rootLine);
 		$urlPreviewEnabled  = $viewDomain . $viewScriptPreviewEnabled . $id . $addGetVars . $anchor;