The invisible prop (help with custom prop)

[cold wolf]

Greets,
I'm having trouble seeing my new prop ingame. It compiles fine and I can see it in Hammer, but not ingame. It's a physics prop, and get this, I compiled the exact same model with just about everything the same in the .gc, and it works perfectly. Anyone come across this problem?

Here's the .gc

$modelname "CombineProps\crate64_phys"
$scale 1.00
$cdmaterials "models\crate64"

$body studio "C:\blah\crate_64_ref.smd"
$sequence "Idle" "C:\blah\crate_64_ref.smd" fps 30

$surfaceprop "metal"

$collisionmodel "C:\blah\crate_64_phys.smd" {
	$concave
	$mass 225.000
}

Thanks in advance for any help offered.

UPDATE: Fixed. I was missing this line:

$keyvalues { "prop_data" { "base" "metal.medium"  } }

See that? KEY VALUE. Who knew?