Thanks for the feedback about the custom uStore themes created by the PS team.
It's a valid point - the theme editor allows you to change the link name for the page in the footer, but not the header.
I'm sure that it is something @Igor will consider in future updates.
If you need to change it urgently, I believe it is set in the localization files:
Of course that does mean you need to set up the development environment to make the change and publish a new theme"
If you need help to get it setup and publish the change, your XMPie or Xerox support team should help you out over webex or other screen-sharing service.