Improve the algorithm for computing k shortest paths

To compute k shortest paths for now we use the HiPOP function KShortestPath which cannot find k different shortest paths in any situation. For example, two bus lines crossing in the center of a manhattan network, there are connected with a transit link there, origin of user is in the left lower corner and destination in the right upper corner.
We find only two different paths with the current algorithm whereas there exists 4 different paths.