If your burning it to a disc, it means you have no choice but to burn it to a Dual Layer disc.
In that case, there's nothing specific you need to do to make it work on a PS3.
Drag the BDMV folder into ImgBurn and that's all you need to you. It must be the BDMV folder. If you have the BDMV folder in another folder (i.e. Demodisk/BDMV/....) and you try to drag that folder, then ImgBurn will likely not flag it is a bluray disc.