Rivera Clubster 45 footswitch - i can't open it

[yeeshkul]

I've got the Clubster 45 here. This guy wants me to add a stomp switch for gain (that is already on the main panel as a push-pull pot) to the original foot pedal instead of reverb. The foot-pedal is plastic and don't wanna break it. I can't see any lock or screws ... any ideas how to open it? I just wanna check out if i can simply remove the reverb and install the gain switch.