How to slingload scripted cargo [MOOSE]

[Scifer]

I placed a Huey and a zone in ME where a slingload object is spawned via script as follows:

-- Spawn cargo

local cargo_template = {
type = 'uh1h_cargo',
mass = 900,
}

local cargo_zone = ZONE:New( 'Cargo Zone' )

local cargo_static = SPAWNSTATIC
:NewFromTemplate( cargo_template, country.id.USA )
:SpawnFromZone( cargo_zone, 0, 'Slingload' )

The problem is the F6 menu item doesn't appear. So I cannot activate the slingload native functions like hook, indicator and smoke.

How can I slingload script spawned static objects?