Since there is not possible to use text formatting when using Instant Web Publishing, I did some research an testing (and a lot of help by Wayne:-), and came up with this solution:
* I downloaded the opensource TinyMCE PHP editor (http://www.tinymce.com/), and put it in the root-directory of the web-server (/Library/WebServer/Documents/).
* Then you have to enable the PHP API in FileMaker Server Advanced (Expand the archive called FM_API_for_PHP_Standalone.zip)
* Then I created a Web Portal in my Layout which I point to a spesific field in the table: "http://192.168.1.106/tinymce/portal/full.php?exisitingText=" & TestHTML::html & "&recordID=" & Get(RecordID)
* What is actually happening, is that the TinyMCE PHP editor is writing to the same field in the active record in FileMaker
* The output is HTML-formatted text, which I use in mail-confirmations
I do not need to convert this HTML to FileMaker formatting in my solution, but I know there is a workaround for this to. I will post the link as soon as I find it....