Thank you, Dr JFBurté, very much. Some notes for others who want the same AND a question on lay-out of the buttons.
You can find the script for common.js at [[Mediawiki:Edittools.js]] You need three things as well: a line in LocalSettings (don't forget to make the extra directory) and 2 php extensions. You can find those at: http://www.mediawiki.org/wiki/Extension:CharInsert
My question. For the lay-out of the buttons I need the following css: class="my-buttons" and class="specialbasic" In which css file should they be placed? Rein ps: what does your last remark : "@+ de jfb "0.02$"" means