This doesn'n work in the current implementation unfortunately. You can use Edit :: Lines manipulation :: Join lines after inserting the respective text at line ends: Edit :: Lines manipulation :: Insert into lines (Alt+I) or replace RE $ >> the string you need.
Or you can try the addon script for multiline replace (limited regexp support currently) http://forum.pspad.com/read.php?2,34061,page=3#msg-35180 -- <http://forum.pspad.com/read.php?2,35456,35460> PSPad freeware editor http://www.pspad.com
