Thank you for your info, i was able to install my LCD.
Later i realised that fbcp was a program that duplicate the screen on the hdmi to the lcd.
So i download the git https://github.com/tasanakorn/rpi-fbcp (couldn't install the fbcp included in the waveshare git), i install it and then in ubuntu mate i add a program to the startup which launch "/usr/local/bin/fbcp &". Now i can see the desktop through the hdmi and the lcd at the same time. In /boot/config.txt i can configure the resolution in the line hdmi_cvt. i'm using 1024x768, and i can see that resolution on the lcd. If i start the pi with no hdmi connection i see the desktop also on the lcd.
The lcd screen is a bit slow, but it is usable.
Sorry for my english.