Create luns and vloume of the new san disk then try to move the database files and other dependecy one by one to the new san disk. Once done with it then remove the old san disk.

Found one similar discussion please check it http://social.msdn.microsoft.com/Forums/en-US/sqldisasterrecovery/thread/9e2503f7-1c8c-425a-87fb-b03aa0ece231