Setting EXIM envelope_to_add

I am unable to set the envelope_to_add parameter within the EXIM Advanced Editor.

I attempt to copy the TRANSPORTMIDDLE section into the working cell above it, change envelope_to_add to include “= true”.

When the dry run happens on save, I receive an error indicating that there are two transport sections.

I would welcome any help to provide instructions on how to set this parameter correctly.  My host is not able to provide instructions.

Thanks.