Set borders to points instead of millimetres

Ever since I downloaded the latest version of Illustrator, the forced convertion between points and millimetres, which take place every bloody time when I use the "Pathfinder" function or the "Expand" function, have given me nothing but pure troubles. Therefore, until I can find a plug-in that allows calculations without point-millimetre conversions, I'm forced to switch from millimetres to points. But there's another problem: I can't seem to set borders to points, but only to millimetres.

Does anyone know how I can set borders to points?

Thanks in advance.