You have to use a raw .bin file or an unscrambled .exe flasher as available on the codeguys site.
It loads all the media reconize, I get the data of my media from dvd identifier and load it into the firmware.
But I have some questions. I have to replace a existing media from the firmware and I can't add a new one, is it normal ?
Yes. You find an explaination on the MCSE homepage.
I can't change the media speed, so I have to replace a media with the speed I want is it a bug ?
Changing the speed id with a 811 firmware should work. As long as you use omnipatcher to change to one of the well known writing strategies this did not matter, even if it would not work, which I have to doubt.
You have to be aware that a 411/811 drive can not burn -R media faster than 4x. That is a hardware limitation.