Adding textarea in editor

Perhaps it isn't clear what I'm trying to do.

I'm trying to add forms using ckeditor. Most form elements get added inside the ckeditor ok until you add a textarea. Because now there is a nested textarea inside the main textarea that gets converted to a ckeditor, the nested textarea closing tags closes the first textarea tag so everything after that is now outside the ckeditor so is uneditable.

I've just found out what you need to do for anyone else that is interested and has had the same problem as me.

You need to encode the html tags within the textarea. I'm using php, so htmlentities() works for me.