A helical sweep gives you a formed wall, bended in two directions (i you are speaking about Pro/Sheetmetal. Usually formed parts cannod be unbended, but for your case create first a small flat wall followed by the helical sweep, so you'll be able to choose the flat surface as reference. I haven't done this for a long time so I'm not 100% sure. I can't even try for myself now because I'm not on the computer that has Pro/E on it.
Let me know if you couldn't do it, and I'll try to give you another answer tomorrow.
I assume you are talking about sheetmetal, but in case you were refering to solid helical sweeps.
I thought it would be possible using the Spinal Bend, Tweak option. I gave it a shot but it did not work because I think it considers the bend based on the current geometry and not percentage along helical sweep. It could be done with a Variable Section Sweep using the Helical Sweep as a reference.
