toyota radio replacement 1995 corolla wagon

I am trying to install a new radio in my 1995 corolla wagon. Trim panel won't come off, and I do not want to break any hidden clips, etc. I have removed the only two visible screws from the bottom of the panel, but still no good. Even looked under the glued-on plastic strip for hidden retainers.

Are there known locations for releasing spring tabs, etc? - Also what tools needed?

thanks,
- WDF -