Don't know what Distro your using but here's how I did it in Mandrake to get rid of that junky star.
Change Menu Icon from Star back to original Kmenu
Here's what I did:
Rename menuk-mdk.png to menuk-mdk-bak.png
Rename kmenu.png to menuk-mdk.png
The folder 32x32 might depend on the size of your startbutton.
note: There are several sizes depending on your default menu size ie: 16x16, 32x32 etc...
you may have to change the menuk-mdk.png in those folders as well.
You may be looking for a different icon name if your not using mandrake but it should be in the same place.