Weird.

I don't have either of those programs but I found a thread on the issue at http://www.realflowforum.com/viewtopic.php?t=1269. They don't really offer any good suggestions (suggestions included using .lwo instead of OBJ, or importing with scale of -1) for fixing it, but at least you know you are not the only one having the problem.

Maybe try flipping it in Carrara prior to export? To do so select the whole thing in the vertex modeler and use EDT>FLIP. it will end up upside down and need to be rotated back so the top is facing up but once you do that it should also be flipped left to right.

Below is a screenshot to show the flip command in use. I used a quick shape with just enough detail to tell if it flipped correctly, duplicated it and then used the flip command on the duplicate, and then finally I rotated the duplicate on the x-axis to get is oriented with the top up instead of down. In my test I had the symmetry plane aligned to one of the leftmost points on my original object, but I don't think that is actually necessary.