External SSD not detected!

Hi,

I'm running Mac OS X Lion (latest version) on a MacBook Pro mid-2010 model. OS X Lion was installed via recovery tools a few days ago.

Today I plugged in a brand new Crucial M4 SSD via USB and it got detected. I restarted the laptop in recovery mode using cmd + R and chose to install Lion on the external SSD. For this I first had to partition the SSD before it showed up as a valid drive where Lion could be installed.

The installation went almost to the end, but then stopped rather strangely for a very long time. So I decided to cancel the installation and restarted the laptop normally. Since then the Crucial M4 SSD is not being detected at all (doesn't even show up in Disk Utility).

Can anyone help me here? What can I do to make it show up?

Thanks in advance.