Problem- 2D Milling Engraving

[ARCOBALENO]

Hi, I have a Roland EGX-300 CNC Desktop engraver which I bought purposely to make Aluminium and Brass metal printing blocks for letterpress and Hotfoil printing. The difficulty that I am experiencing is that with the software that came with the machine I find that it is a little bit limited. I am referring to the 3D engrave. I have purchase Carbide Tipped cutters of 20 degree angle so that when I engrave the image I will not loose from the printing area face when I have to go down to about .9mm deep and where it needs to be engraved both on the inside and out side of graphic. Example a circle, or let say Initial letter R.
Cutting a 2D image with a 3D software seems that the engraver starts working itself from depth upwards instead of the opposite. I have only tried to engrave using soft plastic material to experiment and understand better how things work first and to avoid breaking my tools and the engraver.
Is there anyone who have any suggestions about this problem?
Thank you in advance.