Yes its working. Here is a value of commandHandler (copied from Watch): 

>"\"C:\\USERS\\ADEEL\\APPDATA\\LOCAL\\MICROSOFT\\VISUALSTUDIO\\12.0EXP\\EXTENSIONS\\MADS KRISTENSEN\\WEB ESSENTIALS 2013\\1.4.1\\Resources\\nodejs\\node.exe\" \"C:\\USERS\\ADEEL\\APPDATA\\LOCAL\\MICROSOFT\\VISUALSTUDIO\\12.0EXP\\EXTENSIONS\\MADS KRISTENSEN\\WEB ESSENTIALS 2013\\1.4.1\\Resources\\nodejs\\node_modules\\less\\bin\\lessc\""