Trying to export ID attribute on JSON files

[Sedatyf]

Hi !

I already posted on SideFX forums, but unfortunately, nobody responds me, so I give it a try here !

I'm currently exporting some scattered sim to get some sim (such as explosions) but with particles in json files. For an example, I make a smoke sim with a sphere and a billowy smoke, and in the pyro_import node, below de DOP Import, I lay down a scatter node and a ROP Output Driver node. Thanks to this, I can export some scattered sim with their attribut (such as temperature, velocity, etc.).

The problem is, I'm trying to have an ID Attribute on this particle. I mean by ID, a unique number which corresponds to a particle, like POP Solver.
Someone told me that the POP id is unique across the whole sim and is assigned by a simple counter of new particles. And that's exactly what I'm looking. 

So I did some test to find how to imitate ID system from Pop Solver but on a Pyro Sim. And I found this : below the DOP Import and the scatter node in my pyro_import node, I lay down a AttribWrangle and I say : “i@id = @ptnum;”. And it works pretty good ! But there is a problem. 
When I test this on my POP Solver to compare if my “fake” ID is fair compared to the true ID, we can see a slight different result after 50 frames of sim. 

Because particles dies, and the i@id = @ptnum generate id on the frame and not on the particle. 
The same person told me to try POP Advect and VDB Advect Points, but I don't understand how to use it (I'm still a student who's learning Houdini). 

Does anyone have any idea how to do that properly ? Any advice ?

Thanks,

Sedatyf