Autodesk has provided the HEC-RAS export report for subscription members, now get the Civil3D Reminders Bonus Feature for the extension. Sure you have to do most of the work yourself, but you don't need to fork over money to get it (unless you want too, I won't say no).
In the current report you only get to have the flow direction of the stream go one direction, from a lower station to a higher station value. With the Civil 3D Bonus Feature you get to choose if you want the stream to go the opposite direction. The first step is to add a CheckBox to the AlignToHECRAS form. To open the form double click it in the Project list on the left side of the screen. Then use the Toolbox to add a CheckBox, it fits conveniently below Reach Alignment box. Change the name of the CheckBox in the properties area under (Name) and enter a caption that indicates that the flow direction of the stream will be reversed if the CheckBox is checked.
Now that we have created the CheckBox we can modify the code to reverse the information that is written to the report. HEC-RAS determines the flow based on how stream is drawn. It assumes the first point is upstream and the rest are downstream from it. The code below reverses the information, moving the first point to the back and the last point to the front.
Once the code is finished you are ready to run the report. Once imported you will want to check the data, in accordance to the HEC-RAS user manual, especially to see if the sections are drawn correctly. If they are not use the Reverse Stationing tool to reverse the cross section. HEC-RAS assumes the cross sections are entered from left to right looking downstream. If after using the tool the cross sections are backwards, let me know and I'll see about modifying the code to get them to come in correctly.
Here are the results of running the revised code with the CheckBox checked and unchecked from HEC-RAS: