How to change "next" button to "install"

I'm using MUI2. Before instfiles page I have my custom page that almost never is shown (its creator function immediately returns moving installer to the next page). Like this:
!insertmacro MUI_PAGE_WELCOME
!insertmacro MUI_PAGE_DIRECTORY
Page Custom LockedListShow
!insertmacro MUI_PAGE_INSTFILES
!insertmacro MUI_PAGE_FINISH

How to change "next" button to "install" on MUI_PAGE_DIRECTORY page (this almost always is the last page before instfiles)

After doing GetDlgItem you can do SendMessage $hwndbutton ${WM_SETTEXT} 0 "STR:$(^InstallBtn)"

Edit:


etc (Maybe search first next time?)