How do you open a Greddy gauge?

[KFT0001]

I'm wanting to open up my Greddy gauges to change out the light. The green light clashes so badly with the rest of the interior. I unscrewed the two allen screws on the back, but the cup didn't seperate from the front of the gauge. Has anyone opened one of these up? Please let me know if I'm missing anything or if I just need to pull harder.

 

[KFT0001]

I'm also trying to figure out how to work the playback function. It's hard to figure it out from the Japanese instructions. I have the SM Integration Greddy gauges and I just installed them the night before so I'm still trying to figure them out. I think that I've figured out how to record data, but not sure how to play it back. Anyhow, please respond if you can help me with either of my questions.