I succeded using the following method: Replaced the old SSD with the new bigger SSD, directly out of the package. Put the old SSD in a external housing (OWC Envoy), connected it to the computer via USB and started the computer. It automatically started from the old SSD. Formatted the new SSD and went to appstore for MacOSX. Choose the full installer and used it to install OS X onto the new SSD. Let it restart and could then disconnect the old SSD. A really simple operation.