I came across a similar thing when creating roof splines.. I started by assigning an RC object, to each roof plane spline, then discovered, if I attached several roof plane splines (4 segments each) together, then apply the RC object to them, it works.
Explanation. say you create a roof, using a plane object, with a cut across the centre, you select that centre line and raise it up to create a roof shape. Now you select all the edges and choose create a shape from them, you now have a spline with 7 segments. If you apply an RC object, choose roof tiles and a style and use that spline, it will not work.
To get it to work, you go back to where you have the polygon roof, select each plane (polygon), control click edge selection and you get four edges, then convert to shape, do the same with the other side, you now have two splines with four segments. Now attach one to the other and you have what appears to be one spine, which is in fact two. If you now apply the RC style to this spline, it works..
You may have to reverse the direction of some of them, but that's how you use multiple splines, for one RC object/style... You cannot select ALL the edges and convert to spline, but you can select each face of the object, convert to spline and then attach them all into one. At least that's how I get it to work.
Anyone else with a better solution?