Idiot's Guide to Making Custom Maps?

[Zylithan]

Alright, I'm back with more stupid questions/ better clarification of an old question.

I can make a map now, and assign neighbors. But when I play the map, if I right click on a province, sometimes it selects a different province - especially for unusually shaped provinces. There has to be some way for me to define the geometric boundaries of the provinces. I attached a simple map, as a .bmp ( normally I use .tga)
Depending on where I click in province 5 (as determined by visual red lines) in game, sometimes the computer decides I want info about 5, but often also 1,2,3,4,6. It chooses whichever white dot I am closest to I think. How can I tell it to identify the red lines with the geometrical outline of my provinces?

Thanks!