Today I looked at menu on top of Wammu pages in MSIE and it was displayed completely differently than in Firefox. So another CSS hacking session had to begin to fix the menu look.
Fortunately I found ies4linux which easilly installed MSIE on my Linux computer so that I can test the beast without searching for some Windows installation.
Anyway now it looks almost same in both browsers (there are some minor glitches in MSIE which I'm going to ignore).