Hi Rudy - generally you would use Loft for creating this kind of a surface between 2 profiles.
I think that in this case, it will actually be easiest if you delete your current solid and then build a new larger one using Loft.
Once you delete your short solid, you will have these curves available:
Select the 3 curves on the inside, then run Construct / Loft, and then set some options for the Loft - uncheck "Cap ends", and switch to Loft Style : Straight.
That will create this:
Repeat this process with the outer 3 curves selected to make the outside shell.
Now to join them together, select the 2 curves at the top:
And then run Construct / Planar to make a planar surface there which will be the top cap.
At this point you may want to select your curves and hide or delete them so they aren't in the way.
Select the 3 surfaces (outside wall, inside wall and top cap), and use Edit / Join to join them together. Then select the joined object and run Construct / Planar to fill in the bottom cap and you are done.
Another way that you could approach something like this would be to just build the outer surface and have it as a non-hollow solid with a top and bottom cap right away, and then use Shell to make it hollow, instead of manually constructing the inside wall.
One last note - if you look closely at your result, you can see that there it is kind of broken up with an extra piece in one area here:
This is because your original outside curve is made up of 2 segments there, instead of just one single segment. To help get the cleanest possible model you should delete this extra point in the outline curves so that it doesn't create a little skinny extra surface there.
Hope this helps, let me know if you are stuck on any step.
- Michael
