Need Help Designing a Slide in Solidworks to Sweep across 3 Dimensions

Hi

I work for a playground equipment manufacturer and I'm trying to design a slide in Solidworks which would be made from Stainless Steel.  I can design a slide which sweeps across 2 dimensions but cannot get the profile of the slide to sweep across 3 dimensions without twisting.

I am using a projected curve to initially get the path of the sweep.  I have tried to add guide curves to the sweep to restrict it and prevent this "twisting" but this wont work.  I have attached this file so you can take a look.

The slide obviously needs to be angular so that it can be cut into sections then flattened as sheetmetal to give the final cut profile.

I have used this method or similar to made the 2D slides before.  In this instance it has been used to made an air conditioning duct; http://www.youtube.com/watch?v=VU8EjtD6Tgk.

Below is an image of a similar slide we have made previously to show what we're after.  We didn't use SW to design this one.

I am also looking to design an 8m high spiral slide, but one thing at a time...

If you have any further questions or require anymore information please let me know.

Cheers,

Paul

SolidworksSheet Metal