It's supposed to use the alpha for the phong and all one material.
However it appears to be non-functional.
This is the vmt:
"VertexlitGeneric"
{
"$baseTexture" "models\player\pyro\flamer_belt"
"$phong" "1"
"$phongexponent" "25"
"$phongboost" "1.4"
"$lightwarptexture" "models\lightwarps\weapon_lightwarp"
"$phongfresnelranges" "[1 6 8]"
"$basemapalphaphongmask" "1"
"$rimlight" "1"
"$rimlightboost" "2"
"$rimlightexponent" "2"
"$glowcolor" "1"
// Cloaking
"$cloakPassEnabled" "1"
"Proxies"
{
"weapon_invis"
{
}
"ModelGlowColor"
{
"resultVar" "$glowcolor"
}
"Equals"
{
"srcVar1" "$glowcolor"
"resultVar" "$selfillumtint"
}
"Equals"
{
"srcVar1" "$glowcolor"
"resultVar" "$color2"
}
}
}