Is there a way to randomly flip the UVs of a particle when it spawns?

[Galagast]

Just to update the answer to this. I was also looking for a similar functionality (even posted a request), and found an option in Cascade’s Particle System Required module under the Rendering section called UVFlipping Mode

https://docs.unrealengine.com/latest/INT/Engine/Rendering/ParticleSystems/Reference/Modules/Required/index.html