How to change CSpice inital velocity from an Asteroid SPK file

[despacito]

Hello, I've made a SPK file for the asteroid 7482 (1994 PC1) with Horizon. I wan't to change the inital velocity with cspice, because I want to know where it will be in a future time at that speed. Now I'm using newtons calc for NEO asteroid, but is slow an error increases with time, and cspice for solar system. This is for calculating NEOs asteroid desviation by gravity tractors, so if you now another way to do it let me know, please.
Thanks

 

[despacito]

I found the answer: In this link Newtonian mechanics and a four-order symplectic Candy-Rozmus integration, there is c++ code and phyton. I've modify the c++, so now I calc the inital positions and speeds with cspice and pass then to Newton candy with other asteroid speed. Then I run both to the future to see the asteroid distance to any planet. Just take care about units conversion, cspice frame(ECLIPJ2000) and obverser naif Solar System(0), Used de440.bsp and 2007482(1994 PC1).bsp