Creating Checkbox in MUI

Hi!

I`m creating an installation, and after install finishes it also sends a log file to the webserver. But this feature must be enabled by checking the checkbox on the finishpage. How do i create the checkbox on the finishpage? I`ve searched through forums, and as far as i understand it can be made using

!define MUI_PAGE_CUSTOMFUNCTION_PRE MyFunction
!insertmacro MUI_PAGE_FINISH

Function MyFunction

Code that writes new values to the iospecial.ini file.

FunctionEnd

My question is, how do i get these values? How do i find the coordinates for the ini file for CheckBox, such as Right, Left, Top, Bottom?

I just saw this: hXXp://forums.winamp.com/showthread.php?s=&threadid=223985&highlight=set+checkbox