RAR extension

Hi all, It's not that much, but in Konqueror, in file management mode, when I open a dir and I want to compress some file or dir, I click in the right button of the mouse and it's offered the possibility to compress it to several formats. When I compress with the RAR formart, is created a file with ".RAR" as extension, although for all the other formats the extension are in samll caps. Any hint? Regards Lívio Cipriano