Really need help with surfaceprop feature

[Zentaki]

$modelname "etc\portaria\mesa"

$cdmaterials "models/etc/portaria/mesa"

$jointsurfaceprop "bottom" metal
$jointsurfaceprop "top" rock

$staticprop

$origin 0.0 0.0 0.0 0.0

$scale 1.0

$body "mesa_portaria_ref" "mesa_portaria_ref.smd"

$collisionmodel "mesa_portaria_phys.smd" {
    $concave
    $maxconvexpieces 10000
}

$sequence "idle" "mesa_anims.smd"

$attachment "top" "top" 0.0 0.0 0.0 rotate 0.0 0.0 0.0

$attachment "bottom" "bottom" 0.0 0.0 0.0 rotate 0.0 0.0 0.0

This is what i have and not sure why it still does not work as intended.
Could not find any example on internet. It is missing a lot details on the subject to get it really going.

Why valve did not let the materials to drive this instead? would be much easier. Would use 2 vmt for just one baked image.
But it seems that the only thing that counts is what it is in QC file.
As above QC file i used the joinsurfaceprop command which did not give errors but really did nothing and as a result of not unsing the command surfaceprop the compiler created a default one.
So instead of using the commands from joinsurfaceprop it is just using the default created in compile time.

So is there a way to make it? maybe some way to put together the surfaceprop to point to the jointsurfaceprop.

In valve Developer Community you can find this:
In models:
- It is unclear whether a model's mass is calculated from $surfaceprop or prop_data
- Surface props can be defined for individual bones with $jointsurfaceprop

It is hilarious how they state it is unclear, really? if you valve don't know your stuff how could anyone?!!!!Phew needed to put that one out!

You can see that it is said that a model could have multiple surfaceprops using bones feature.

There are not really examples how to apply the information.