For example: if you have to do an outbound until 8 miles out and then start a turn inbound, the LNAV starts the turn 6 miles out or even before that, it then draws the curve before the 2 waypoints. In this example you type VOR030/8 and next VOR360/8, it does something like on the drawing. Can anyone explain how to let it fly over the waypoint and start to turn after 8 DME?(the black line is the desired track, the pink one is what FMS makes of it).

You can't unless you insert a "pseudo" waypoint to force the aircraft to fly over the desired waypoint. By design, the aircraft "flys by" the waypoint and not "over" it. Use Heading Select instead of LNAV.

Here's an explanation from one of the developrs of 767 PIC.

Is it the same way on the real 767 FMS? Or are those waypoints "fly-over" -waypoints?

The real 767 FMS has fly over waypoints hard coded into the system.They are hardcoded into the AIRAC Data. Conditional Waypoints and Intercepts are handled the same way. Intercepts can be coded in PIC using some jiggerry pokerey as well.Mark