round bottom div corners using floating images cause undesired extra space after round corner images

[Marek Mänd]

minimal relevant testcase:
http://www.hot.ee/idaliiga/marek/lists/roundcorners/visual-round-corners-test.htm

IE ability to understand CSS makes my hair gray:

1)
Why arent the round corner images the at the very bottom of
DIVs.mainmenucolumn IE5. Mozilla displays diffrently from it as I want
to. Even Opera6.05 doesnt have that problem. How can it be workarouded
for IE5, how do I get rid of that extra space after the round corner images?

2)
How can I make those DIVs having equal height, whereas that height is
the height of the tallest one of those ? (without tables, solution
should work also in IE5+, the amount of links is unknown, comes from
database).