Using vCO in Web Client

Hi,

I would like to use Orchestrator within my Web Client.  I have looked at my configuration and the Web Client plugin is installed (or so it claims within vCO Configuration page) but when I log into my Web Client I can't see it.

I am using vCenter 5.0 (with vCO 5.5), so am assuming this is the problem and I would need to upgrade to at least 5.1?