To the best of my knowledge all you can do is fudge it up in solids however you can do it using surfaces. The
"rulesurf" command will make a mesh from one polyline to the other as long as they are not closed (see attached pic). Be sure to set your "surftab1" & "surftab2" to a high resolution say around 64 depending on the detail you want. In addition to a high surftab you might also have to drag some grips around once you have made your mesh so it meets the corners properly.
But it just seems to easy doesn't it? you can't project profiles using "SOLPROF" of a mesh as it won't recognise it. But for a shaded 3D view it will solve your drama's and I'm sure you will be able to fudge something up for the 2D views.
Hope this helps mate,
Stewy C.
rulesurf.jpg