There are several vector drawing programmes in the repositories. You mention
two.

There is also Sodipodi, Xara Xtreme and Inkscape, which is the best IMO. Both
should install and give you icons under Graphics as I have them installed.

See: http://en.wikipedia.org/wiki/Category:Linux_vector_graphics_software
For CAD: http://tldp.org/LDP/LGNET/issue54/frost.html

If a programme does not give you an icon you can create one easily. On the
desktop you right click and choose Create Lanucher.. You can type the load
command and change the icon. You can also create launcher for the panel by right
clicking on it and choosing Add to Panel. choose Custom Launcher from the menu.
You can add one to the menu by going to System, Preferences, Main Menu.

Ususally this is done for you. In rare cases it does not put one where you think
that it should be, gives it a different name or not at all. Fortunately it is
flexible and easy to fix.