Hello again all and thank you for your help.
I have managed to program the attiny85 and everything works just as you specified.
I just have a little problem with BOD level.
Firstly I have use the BOD level at 4.3V. Everything was working okay but sometimes the LEDS just froze. I gues that the voltage droped bellow 4.3 and attiny entered the sleep mode. This isn't a big problem because the voltage dropes sometime bellow 4.3v but just for a few miliseconds. The problem is that the leds just freezes too even with the attiny in sleep mode and theoretically there is no chance for the 4.3v to get higher because the leds "eat" all the power.
Isnt any way that I can give a command like "strip.show();" and reboot to turn the leds to OFF just before the reset pin goes low because of voltage drop ?
In this case the voltage will go high and attiny will reboot with no problems.
For the moment I am using it like this and connecting and disconnecting the power supply when I see the leds freezes.
I also tried to use with externall Xtal, same problem.