OK, here are the pictures you were asking for. Sounds like you are taking on something a bit more complex. Not saying it can't be done, but I would have to think long and hard. Hope these pictures give you some ideas, PM me if you would like.
Sewer connections and plumbing:
Inside wet bin, black tank on left, grey tank on right
New extension to outside connector
New extension outside connectior. Note that neither connector will go through the port, soit had to be assembled in place.
New extension, another view
New extension, outside connector. Note that is is usually closed with a cap when not in use. The velcro straps hot it in place while traveling. Note cap hanging from strap to keep from losing it.
Hope these pictures are what you are asking.
