This is the exciting point where you need to start messing with the skin. The easiest is to just change the graphics (eg plane) to something less intrusive. First thing I did was to change the birthday icon to a small red dot - barely visible. You need to open the xxx/rainlendar2/skins/xxxx.r2skin file (as a zip file) and edit the graphics you need changed. The Gimp highly recommended (and free). Or, of course, you can be even braver and start messing with the XML files. Not too hard, but it tends to take a lot of time (playing with colours instead of icons, as you want). I have basically done horrid things to the Shadow skin, and probably would offend the designer no end, but it works for me.
PS - you may of course try the different skins available - maybe someone has made a scheme to your liking.