How to replace Ubuntu logos & brand-marks in custom distro?

I was trying to create an ubuntu based distro in KDE and want to know that is there any way to replace kubuntu & ubuntu logos or brand marks ?

Like in kde startup menu has kubuntu's logo how can I replace all the similar logos?

And where all the logos are located in Ubuntu distro. Working on ubuntu & kubuntu 12.04.03

OK after searching through the Linux file system, i found few files (logos) which can be replaced to prevent copyright violation.

All the files resides in

      /usr/share/icons &
      /usr/share/pixmaps

File names to replace are (All files are in png or svg file format)

   start-here 
   distributor-logo
   ubuntu-logo 

I will add more names if i will find in future. Also edit these files as per your requirements /etc/issues.net /etc/lsb-release /etc/issue

but then you have to edit /usr/share/pyshared/aptsources/distro.py

and assign values of original lsb-release file to variables like

       self.id="Ubuntu"
       self.codename="precise"
       self.description="Ubuntu 12.04.02 LTS"
       self.release= 12.04

Thanks.