showing disabled sections

I want to show a section on the components page but I dont want to allow users to disable it, or not install it. How can I show the section, and have it install, but not allow it to be disabled?

Or, if for some reason this is not possible, how can I disable the next button if a chosen section is not selected on the components page?

Add this one line below the section begining:

SectionIn RO

It should looks like this (example):

Section "Program files" SEC01

SectionIn RO

  SetOutPath "$INSTDIR"

  SetOverwrite ifnewer

  File ">your file(s)<"

SectionEnd



Section "Additional files" SEC02

  SetOutPath "$INSTDIR"

  SetOverwrite ifnewer

  File ">your file(s)<"

SectionEnd

In this example is "Program files" required, but "Additional files" not.

Add SectionIn RO one line below the section begining, wich section should be required.

thanks