Hi Danilo,
When I was doing the dreaded heater lever replacement, I had the speaker, radio, and heater control levers out and it seemed that I could have gotten to the back of the speedometer to remove it. However, I didn't try it so I can't be totally sure.
If you do take them all out be very careful of the center gauge. It has an oil line connected to the engine and can spill all over you and your interior!
Pete S.