Trouble with castCollision in T2D

I try to create some jumping system for a platformer game, there is jumping based on angle and power. I use for this setImpulseForcePolar() and setConstantForcePolar() (for gravity). But i must check situation when player lands on the edge of platform. But simulation of jump with castCollision fails when I set setImpulseForcePolar() to player - castCollision is return strange collision position or return nothing. I've set different time from 1sec to 1000sec and I'm sure speed isn't 0 - my player is jumping right.
(Player has custom collision poly which is rectangle smaller than sprite size)
Please help me!