Defining my work piece weight et my tool weight

You need to use the service routine LoadID, so long as your robot has that option, Load identification and collision detection.  Tooldata is for you end effector, Loaddata is for you workpiece.

You need to call the service routine LoadID.  Actually, prior to that, you need to define any armloads (any other things mounted on the robot arm, not end-of-arm).  That will be in your moc.cfg.  Follow the on screen instructions carefully.  You would define the EOAT first, then run the routine once more to identify the payload.  Again, that would be loaddata.  All of this can be found in the user guide for Load identification and collision detection guide.  It is possible to go into your tooldata and manually enter the tool mass, cog and moments of inertia (ix,iy, and iz).  You can do the same with your loaddata.