Michael,

"You can actually just do an extrude if you want - extrude each curve out to a surface and then select the 2 surfaces and run the Isect command. That way you will be able to get the full Extrude interface because you'll really be using Extrude."

that's exactly what I meant and better yet, it's already implemented. A little but though, there is no way to figure this out from the help files...

Thanks
Felix