If you have some highlighted text in Notetab , why not ask Rebol to process it? Here's a couple of files that will get you there. Consider these as a starting point for your own additions.
This script takes the input passed from Notetab and massages it a little bit, so that it can be used with Rebol cleanly.
Just make sure this can be found when it is called. I put mine in the directory with the rebol binary. I haven't tried it but you may consider trying it in the notetab binary directory.
This is a Notetab clipbook library that will use the above rebol script to process selected text within you Notetab window. Just select the text click on the clip entry and Rebol will process your text and return the result. I hope you find it useful.
This particular clipbook uses scripts from this page plus the script clean-script.r that can be found in the library at www.rebol.com
Put this with your other clipbook libraries.
While not a particularly outstanding example of scripting, I suggest you download this as it is referred to by the clipbook.
Put this in a directory called "library" below where you put notetab-gateway.r
Drop me a line if you have better instructions on installing this stuff.