Pre-Render Script over network - Working method!

For my specific reason I needed to send a render of a selected object. I've been trying unsuccessfully to send a job to render over the network using the "setRenderType #selected" active to render a selected item only.
(in combination with VRay's "renderers.current.imageSampler_renderMask_type = 2")

Problem is - once it gets to the network, my object is no longer selected.

So I delved into the Pre-Render script. However, even though I managed to create a small single-line script that selects my object and set it to run before the render (pre-render) - Max would constantly ignore it:

preRendScript = @"\\server\PreRender_selectNet.ms"
usePreRendScript = true

It would always come up saying that it cannot render because no object is selected. It was trying to render in "selected" mode before actually making a selection.

So I tried using a preRender callbacks script:

callbacks.removescripts id:#net_select
txt = "for n in objects do if matchpattern n.name pattern:\"Net*\" == true do select n\n"
callbacks.addscript #preRender txt id:#net_select

That too failed to start before the render.

So - here's the solution:
Use a callbacks that would call a script when the file opens instead of before it renders. This method did the job:

callbacks.removescripts id:#net_select
txt = "for n in objects do if matchpattern n.name pattern:\"Net*\" == true do select n\n"
callbacks.addScript #filePostOpen txt id:#net_select persistent:true

Now I can properly run Pre-Render scripts that would be embedded in the file and would be distributed with the file over a network render farm and run properly.

Enjoy.