Interpolate Cross Sections

I have created cross sections in GIS (ArcView 9.1) and have exported them into HEC-RAS. I edited the cross sections for correct channel depths and need to create a new TIN in GIS for mapping. When I interpolate the cross sections they do not follow the stream centerlines. Is there any way to interpolate along the stream centerlines?

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The interpolation in RAS is linear and doesn't follow the river line. You will have to export the cross sections to the GIS and create 3D breaklines that represent the channel and overbank areas.

GeoRAS can be used to do this using the Levee Tool.

Then use the 3D breaklines to add back into your TIN. Not the "easy" way one would hope to do it, but fairly easy and mindless.