Have done a similar thing with copying the rich text item from another doc before. Did the read only bit slightly differently tho...just set the readonly attribute in the html attributes for the rt field and off you go. e.g. you may have "width=\"200\" height=\"100\" readonly=\"readonly\"" in the attributes which will give a readonly scrollable textarea with all of the text in it while leaving the rest of the form as editable.
Have done a similar thing with copying the rich text item from another doc before. Did the read only bit slightly differently tho...just set the readonly attribute in the html attributes for the rt field and off you go. e.g. you may have "width=\"200\" height=\"100\" readonly=\"readonly\"" in the attributes which will give a readonly scrollable textarea with all of the text in it while leaving the rest of the form as editable.