I know this is an upstream bug, but they have fixed it in their trunk. I have been looking it, and I created a patch to backport this fix to current 0.97. And it is working now in KDE4 (as well as KDE3) systray.
Could you apply in a revbump?
Created attachment 149918 [details, diff]
patch for a working systray icon in kde4
I think this was a bug in KDE4 itself and was fixed in KDE 4.0.2.
get kde 4.0.2 then...
It WAS NOT fixed in KDE 4.0.2 because I was using trunk (later than 4.0.2 release) when I discovered that bug. And, the fixed it upstream (and this is the reason I tried to backport it). If you google a bit, you could see the problem :)
So I reopen
is that patch in 0.97.2 ? Has it been reported upstream ?
Sorry for my late answer, I have just installed KDE from svn trunk (4.2), and it seems it is working again as expected.
If anyone can try in kde 4.1 and see if it is fixed in 4.1 I could close the bug.
It seems its been fixed in KDE 4.1