Upgrading from Alfresco 4.2.c to Alfresco 5.1

Hi friends....

I am want to upgrade my alfresco 4.2.c to Alfresco 5.1 straightaway...

My question is

(1) Is it possible?

(2) Can I do for direct upgrade from version 4.2.c backup to Alfresco 5.1 ?

(2) If so, what are steps to be followed, apart from steps mentioned below

http://fcorti.com/2013/02/12/alfresco-restore/

Please guide .....

Thanks

Mahesh