Activate view from custom command

Hi

I am trying to run a javascript module using a custom command (is this the correct method?) in my toolbar. 

In Essentials it looks like this:

Command: ActivateView

Command Parameter: ToolUIView

Unsure of the command/operation to run this and the syntax of string required. I know how to run it from WF5 but would like to run it directly in Web Studio.

Thanks for any help,

Vincent