For anybody interested, you can use following snippet:
FMOD::Studio::System* StudioSystem = IFMODStudioModule::Get().GetStudioSystem(EFMODSystemContext::Runtime);
if (StudioSystem != nullptr)
{
FMOD_RESULT Result = StudioSystem->setParameterByNameWithLabel("Footstep_Material", Param);
if (Result != FMOD_OK)
{
UE_LOG(LogTemp, Warning, TEXT("SetFootstepParam(): Failed to set audio parameter, %d"),(int)Result);
}
}